If I had to give advice to people at different points in their life, that advice would change and factor in where they are, what they can do and where they're going. Since nobody is giving advice to a newborn, I'll start with advice for parents of a newborn and then move on to advice for young teens, mid teens, when you become an adult, early to mid twenties, 30, 40, 50, 65.
When I was a teen, I wanted a Ferrari; when I was in my late 20's those 2000 Modena 360's were down to about $60k and if it never needed repairs I might have made money on buying one if I could afford it. Now, I've got a bit of wisdom and at any age I'd just buy a reliable Toyota Camry or Nissan Altima. Japanese engineers make these cars knowing they won't be perfectly maintained, German engineers expect you to maintain it exactly as described in the manual; also German & Italian cars are more expensive to maintain. Japanese cars manufactured in USA don't offer any of the cheaper expected replacement parts you'd expect of American cars, but over all they are reasonable to maintain. My car was 4 years old when I bought it with 38k miles and that lead to a very nice savings on a comfortable and reliable car that can go fast when you want it to. If you want to drive a fast car, rent a supercar and a track rental if you're wealthy and if you're not there's 'Ferrari Experience' and 'Lamborghini Experience' groupon's and other deals around $100-500 so you can have that experience on an agility course with a professional driver sitting next to you for safety (ride along experience is cheaper and you don't get to drive, driving experience you get to drive; I paid $100 to drive but they seem to be $400 to drive and $100 to be in ride along but still worth it in either case if you want to experience a super car.) As to when to sell, if the annual repair costs equal or exceed expected annual interest and depreciation on a slightly used (2-6 years, under 50k miles) car then it's time to sell or trade in and you should always consider living near work and using rideshare services and decide if that represents a significant savings to payments, insurance, gas and repairs.
If thin, all you have to do is build muscle; if fat you should lose fat and then build muscle. But, you should do it now and don't miss time! If fat/overweight/obese, calculate your BMR and structure a diet around a 500 calorie deficit and eat twice as many grams of protein compared to carbs and increse the deficit by 100 calories if you don't lose at least 1lb in a week 3 weeks in a row and within 3 months you should be much slimmer. It's good to take a break each 3 months of weightloss dieting, try and hold your new weight for 1 month (go on daily walks, lift weights, don't consume more than your new BMR -recalculate it after weight loss- and then start again with a 500 calorie deficit from your new BMR.) Once you're at least reasonably slim, focus on building lean muscle, no need to 'bulk up' as you're probably not going to be financially successful as a bodybuilder or NFL player; just build 1lb of lean mass per 6 weeks of training (probably more the first year, but over 2-4 years this is a good average growth rate during growth or lean bulk times when doing hypertrophy training) by using a 300 calorie surplus and training each muscle 2-3 times per week using the general concepts listed on this page. Those extra calories should be used up from your workout and in the process of building muscle. I didn't follow the first part, in my Freshman year of high school I had 14" arms and a 43" waist; by the end of Junior year I had 19.5" arms and still had a 43" waist (I'm now slimmer as I approach my 41st birthday than I was in most of high school, towards the end I got down to a 38" waist and my arms were 19 5/8" natural in high school, not even using creatine.) I tried to slim down when I was home schooled in 7th grade, if I had known my current diet of fritatta's and casseroles (no starch, all carbs from veggies and much lower calories than I'd do as a younger person) I may have been slim in high school.
This page is mostly geared towards non-business choices, as the entrepreneurial spirit hits those both at the top of the Ivy League and professional world as well as those who don't do well in traditional education and professional environments. Starting a business is hard, most are better off with a good job and SP500 investments; some are better off investing in individual stocks or starting their own business. If you decide to start a business, you may take different paths than listed here or make adjustments. I suggest going to college (avoid debt if you can) and building a business on a shoestring, it may be easier to live with parents if going to college while building a business; in 4 years you should be able to build it enough to know if you want to expand (with or without investors), keep it the same or quit and get a normal job. You may start a business young or when in your 40's or even when you retire from a regular job and now have time and income from retirement plans.
Basic strategy for investing is dollar cost averaging each week into SP500 (usually in the form of a low fee index fund, 0.1% is the most in annual fees you should pay) and never selling (though you can sell 4-6% each year when you retire), if you do that; you won't need the benefit of tax deferred 401k or tax advantaged Roth IRA. However, if you fully utilize Roth IRA (and if your employer doesn't match contributions then a Roth 401k may be a good idea as well if you don't need tax savings) you may be able to benefit from tax free income in retirement. To compare it to blackjack, basic strategy gets fair value and advantage play like card counting gets a bit extra; if you spend time studying the market then you can get to the point that you can pick stocks with the best of them and might vastly outperform the market on a small scale in your Roth IRA (though 401k's are rarely set up for trading, a mix of 40% Nasdaq 100 and 60% SP 500 is probably the most agressive mix for 401k's.) For example, many stocks rose 20-50% after Donald Trump was elected; some large liquid investments went up 300% in a mere 2 months and many in the Quantum computer industry went up 10x (those were the only ones I would never have predicted, that field isn't expected to be viable for a long time; the only thing it has to do with the president is market euphoria.)
22 years ago, I bought the Carlton Sheets real estate investing course; the 2003-2007 real estate boom was dramatic but prices were too high for new entrants by 2005 in most cases and the market crashed in 2008 (even well off people had trouble getting a mortgage when prices were low.) Prices are through the roof and it can often be cheaper to rent (as most of those rentals were bought at interest rates lower than today,) but if you buy you may be able to not only regain your monthly payments when you sell but you may actually make a profit living there. There's the possibility that prices will go down (as they did from 1987-1994, and again from 2008-2009 and prices were still reasonable in 2016) but there's not that many cases of wide spread price crashes in real estate so it's hard to tell if it will happen again in our lifetime (may happen, or not; nobody can tell.) My best advice is improve your credit score and have someone willing to be a cosigner if you need one, veterans have access to VA loans with good interest rates and low down payment terms. Today it's cheaper to rent a 6 bedroom McMansion and have 5 roommates than to rent a small studio apartment in some cases, if interest rates go down; it may make more sense to buy (but so far prices haven't gone down much at all despite interest rates dramatically cutting down buying power.) Finally, I encourage paying your mortgage biweekly (ie half of your monthly payment each 2 weeks) which gives you an extra month of payments a year and results in paying off a 30 year mortgage in 21 years.
In an ideal world, you could put thousands of dollars into an investment for your newborn; but many parents are struggling to pay rent and this isn't practical. My advice is to put $3 a day into sp500 for their retirement from birth until age 4, by age 65 they'll have $1.7 million if it continues to grow at 10%. If you put $3/day from age 5-12 and get 10% compounded growth, that's $15k for a car on their 16th birthday (unless they just get a rideshare each time they need a car, which some do today; as insurance/gas/car may be a worse deal than occasional rideshare.) If you invest $10 a day after age 12 until age 25, you could fund their college education for whatever scholarships and grants don't cover; at today's prices of state schools (not even community college) and have $47k for a downpayment on their first home. If you have the resources, give your kids a job as early as possible (even if they're an infant, they can be a spokesmodel for your business) and put all of their income into tax deferred & roth IRA investments. You may have to form a separate corporation to allow 100% matching of 401k without having to give it to every employee down to the janitor (nothing against janitors.) Now that you've planned for your child's future, here's my advice for your future. In todays world, both parents should work; this is the best chance at middle to upper middle class. Today in 2025 the median home price is around $370k, in 1 year a working couple living at your parents house can save bare minimum 3.5% FHA down payment on a house. If you want to give your kids an extra edge in making friends and getting girlfriends (women don't need help finding boyfriends) consider getting a house with a pool and hot tub (new pools are generally too expensive to install, but they don't increase the buying price much.) Both parents should make an effort to stay in shape, go for daily walks and full body weight lifting workouts at least 2-3 times a week (split schedules a minimum of 4 days a week.) Have a family vacation at least 1 week a year (ideally 2 weeks) and at least one weekend getaway. Max out your 401k first if there is employer matching (up to the match limit) and then focus on Roth IRA contributions, if there's still money left then put the rest in the 401k up to the total contribution limit. Try to grow your income by looking for opportunities to get higher salary such as shopping around your skills to see if competitors pay significantly more (and offer your current employer a chance to keep you if you get a higher offer from a company with a reputation for good company culture. Last but not least, eat real food (not fast food, junk food, white bread, etc) and don't drink.
This is a relatively simple time of life. If you have a job, it's most likely either babysitting or mowing lawns (unless you're advanced and offering digital marketing services, though that's rare this young.) My advice, get good grades, eat right, get a good night sleep each night, try to make some extra income with simple side gigs like those, ideally put money into simple long term investing options like low fee SP500 index funds, make lots of friends and get into exercise. Before 14, I'd say sprinting, situps, pushups, chins and dips is a sufficient workout plan; some may be advanced and do gymnast ring exercises. When turning 14, with parents your parents permission I suggest three days a week (M W F) you do a full body free weights workout of 3 sets of 8-12 reps each (incline dumbbell bench press, squat, lat pulldowns, curl, triceps press, overhead press, calve raises, situps, in whatever order you find best.) Once you know you're weights for each, work up to 3 sets of 12 and then add 2.5 lbs to each side of the bar (or 5lbs total) and do 3 sets of at least 8 reps and do that until you can do 3 sets of 12 and then add another 5lbs total. This combined with a healthy diet should suffice the beginner in a health and fitness lifestyle, eventually you'll need more exercises and/or can't continue adding 5lbs every 1-4 weeks and you'll move on to an intermediate program. Females may benefit from limiting sugar during that time of the month and drinking chia seed drink or lychee drink instead. Also consider a soy isoflavone pill, for snacks kiwi or mango are good as they balance Ph. When it comes to diet, in addition to the other advice I've given, I advise following the general Kosher guidelines (I don't mean food blessed by a Rabbi, but no shellfish and no pork; nothing unclean.) If you come up with a business that can be started with your skills at such a young age, it's a blessing; you may fail fast and cheap or you may be so successful you get out of the rat race before 18.
At this point, you may be working, dating, getting a car. You might not need a car, as rideshare options are often cheaper; but just like having a pool if you have a car it's easier to get a date. I'd encourage learning digital marketing, those that do it have much more money often while still in high school than those working in fast food. If you can get a job in a popular store in the mall that might be better than fast food, but it's not as popular in youth culture as it used to be. If you have a job or earned income, you can contribute to a Roth IRA; some day that will mean tax free money in retirement. You might want money for college, a house, vacations (spring break or a graduation trip), a car; all worthy pursuits. My advice, put it in SP500 and over time it's the best steady growth; even when it crashed it was back in a few years and with dollar cost averaging it was not a big deal after 2-3 years. For exercise, either continue on the beginner plan described above or consider either a 6 day a week 1 muscle per day workout or a push/pull split workout (you could even do 1 month specialization workouts for arms, delts or abs, look up workouts that seem practical and try them out.) For food, eat right and if you're a guy consider a 300 calorie surplus if trying to gain muscle with minimal fat gain (shoot for 1 gram of protein per lb of bodyweight for muscle gain.) You may want to get some micro gainz plates that for $50 you have 0.25-1.25lb plates for making small adjustments to your weights once you aren't gaining 5lbs every 1-3 weeks on major lifts and for small muscle exercises. You can also do programs like 5x5 for a short term increase, which is 2 warmups and 3 sets of your 5 rep max and increasing once you can do 5 reps for 3 sets. You may want to work as a trade apprentice or start in digital marketing, these can put you well ahead of others in income early on. Maximize all academic opportunities for grants and scholarships (like Bright Futures.) I wish I had advice for dating, some great women have taken interest in me (simple twist of fate reasons that it didn't work out or happen in many cases) but I never had a calculated way to meet women (I was advised to take dance classes and pilates classes, I'll try that soon.) I will say, the time when you'll be around the most potential dates is generally when you're a kid in high school; as online classes have cut down the college opportunities. If you can start a business this young, go for it; either fail fast and cheap or make it big at a super young age.
This is a video about growing up and cultural rituals, but there's a few F words; viewer discretion advised.
If you can afford it, I suggest a graduation trip with friends/significant other; 2-12 weeks in Europe can be a great experience. The same diet and exercise advice given earlier still applies, you figure out your own goals and make adjustments as needed. You're starting your path to a career, you may get a job, go to college, work on a trade, business etc. If you can, I suggest living at home for as long as possible as it allows saving most of your income to invest/start a business/buy a home all that much faster. As hard as it is, keep investing as much as possible. Ideally, you'd max out a Roth IRA (currently $7000, likely going up) and 401k (23000 or so) as early as possible and every year until retirement into low fee SP500 index funds; but all you have to do to retire a millionaire is put $10/day in your Roth from 18-22 (4 years.) I strongly suggest community college with guaranteed admission to state Uni's unless you can get into Ivy league schools it's just as good as anything and it's much cheaper. Look for every scholarship and grant opportunity to save money on college. In college, your best opportunities to date are Frat parties, nightclubs catering to the school, people you meet in classes; generally women avoid meeting new people if someone meets them just walking around (maybe at the library or food court/cafeteria.) Either by 18 or up to mid 20's, you might max out even on half pound weight increases each week; I like Mike Brown's sticking point smashers which allow adding 1/3 oz to each side of the bar (I also do something similar with his 3" thick tapered wrist roller for forearms.) Of course, you might still be gaining strength or may have had injuries (often outside the gym, I've rarely been injured in the gym) and had to start over again. If you start an exercise with just the bare bar, at 5lbs a week you'd be at 300lbs in a year; so even at 1/3 that progress after 6 months in 5 years you'd be lifting 500lbs (quite possible on deadlifts for long armed people and squats for shorter people, though some may eclipse these lifts on all 3 powerlifting exercises.)
At this point you either have a business, just graduated college or are in advanced studies like med school or law school; unless something didn't work out and your plans got delayed. If the later is the case, then fret not; just keep plugging away and get back on course as fast as you can. You want to focus on building your business or career and buying a house; all while contributing to retirement plans and staying fit. Hopefully you have a long term relationship by now, as it gets harder every year. Consider your mortgage length, you might want to keep it at 30 year; but make sure there's no early payment penalty and as long as you can afford it pay half biweekly and you'll wind up making 1 extra payment a month which pays it off in 20 years rather than 30. When you graduate college is probably the second best time to spend some time travelling.
Starting to get to prime earnings years, keep on doing what has been working. If you don't already have a long term relationship, go out of your way to get one; it won't be long before people won't hang out with you because "they only want couple friends." Of course, just like all age ranges you should eat right and keep active. The biggest change here is you want to take care of your scalp and prevent hair loss, if it starts thinning see a doctor and ask if they recommend minoxidil, topical finasteride or something else (I don't suggest oral finasteride even with doctor encouragement, as it has side effects; minoxidil is non-prescription but may irritate the scalp and you just stop using it if that happens.) Always ask about all known side effects when discussing it with your doctor. I strongly encourage travelling the world at least 1 week a year (ideally 2 weeks) and a camping trip in the fall.
Same as the last entry, but these are prime earning years and now is when people only want couple friends. In addition to scalp health and staying fit and healthy, I suggest taking extra care to your skin to stay as young as possible. Hyuralonic acid may help, moisturizer, see a dermatologist and ask for advice on maintaining as much youth as possible.
Main note here is that at 50 you can contribute more to retirement plans (401k is 31k and Roth IRA is 8000, may be much more in the future) so continue to max them out as I hope you have for a long time. Let's say you just start now, at 10% you'll have $1.2 million. Of course, you'll need at least $65k a year to do this; but that's a very reasonable income.
Of course, you can retire whenever you can afford to and no longer wish to work; this is simply the traditional retirement age (there are sharp and fit people at age 90+, I just saw a 102 year old man who goes canoeing and running.) At this point, you should own a home (if you want a permanant place to reside, some people want to move every few years) and have retirement investments. Continue to focus on your health, as it's better to be healthy in a Toyota than decrepit in a Rolls Royce; but you can have health and wealth and that's the best of all. You may decide to take up tai chi and/or yoga, which both help stay young and vibrant. As you get older, make sure to find new friends as friends pass on; friendship is one of the keys to avoiding early mortality. At this age, you may have grandkids; if you can afford to I encourage investing in their education, teaching them your wisdom, invest in a viable businesses they may have, teach them about investing and help them with buying their first house. Whether you can help them financially, or in giving your knowledge, or both; help them however you can and help your kids figure out parenting (too hard for me, best of luck to parents.) You may also find mentoring to be fulfilling. If you take care of yourself, you should have energy to enjoy your golden years; make sure to do some travelling.
To showcase what's possible at age 69, here's Mike Brown bench pressing 120lb dumbbells!