1. Don't smoke. If you've started, stop immediately.
"If you could see me now, I'm down on my poor, crackling knees begging you to at least consider stopping smoking," writes Quora user Cyndi Perlman Fink. It’s expensive, smells gross, and is 100% guaranteed to cause health problems. Want to be cancer-free at 50? Stop smoking.
2. Stop eating crap.
"You can make a lot of money in 20s, 30s, 40s, 50s,...90s to buy the whole world when you are at age 50 or beyond," writes Quora user Sireesha Chilakamarri. "But, you cannot buy your health. Give up on fast food right now at age 30."
3. Maintain (or repair) relationships with parents and siblings.
"...Chances are you've come across ideas and changed in ways that mean you don't see eye to eye with them on many issues. But then - that's part of what a family can help with - to learn to get along with people you don't agree with on many issues," writes Quora user Robert Walker.
"I come from a family which is very argumentative. If you didn't understand the situation you might at times think we hate each other. But it isn't like that at all. Rather, we free to speak our minds because the family ties are so strong."
4. Stop going out in the sun without sunblock.
"I was stupid. I didn't listen. Do you want wrinkles and thin skin from sun damage like I have and do you want bruises from just lightly touching the side of a box and having your skin peel off? Go ahead, enjoy lying in the sun without sunblock," writes Quora user Cyndi Perlman Fink.
5. Exercise regularly.

Build an active lifestyle now, and when you're 50 you won’t be stuck in a Rascal. "Don't gain weight. Exercise. Keep your weight at a normal level that's good for your body," continues Cyndi Perlman Fink. "Weight does all kinds of bad things for your body. I've been fat, I've been thin, thin is healthier."
6. Start saving money. Even if it's just a tiny bit.
Save money. I know this is a boring, trite, and unsexy suggestion, but it's true," writes Quora user Cliff Gilley. "In your 30s, the average person has a lot of disposable income, some of which can almost always easily be set aside for use later in life. Plus, building the habit of saving early means you'll continue it further down the line."
7. Learn to be content with what you have.
"...Happiness is what matters far more than worldly success," writes Quora user Robert Walker. "If you are content with what you have then you may be a bit less likely to end up a millionaire, but you will have a happier life. And if you do become a wealthy person - is no reason why not, you'll be a more happy, fulfilled and productive wealthy person."
8. Don't delay pursuing your life goals.
"Want to buy a house? Have kids? Write a book? Get a second degree or advanced degree? Change your career? Learn to play a new musical instrument? Learn to cook gourmet meals? Try scuba diving? Run for public office? Start a business and be self-employed? Then start today," writes Quora user Bill Karwin. "It's easy to put things off. "I'll get to that someday." But it's really true that time starts accelerating as you enter your 30's, and it keeps accelerating. The time that you'll get around to those dreams should be now."
9. Get some sleep.

"Use stellar sleep hygiene," writes Quora user Nan Waldman. "A dark room or sleep shades will block out the light. No bright screens before bedtime. Go to sleep at the same time and wake up at the same time."
10. Take care of your teeth.
"...Go to the freaking dentist already," writes Quora user Caroline Zelonka. "Get your little cavities fixed as they come up. Unlike many body health issues, dental problems only get worse -- and things like crowns and implants are uncomfortable, time-consuming and expensive (like close to five figures per tooth for an extraction, implant, and crown). If you have a good savings and income stream, the bills won't be the painful thing -- but there's no getting around the pain and the time suck."