The 7 worst mistakes you can make in your 30s

If you developed a spending habit in your 20s at the expense of saving for your future, it's not too late.

An anonymous poster wrote that when his salary increased dramatically, he started spending excessively on things like expensive cars, a motorcycle, and a boat. Only in retrospect did he realize the danger of burning through money.

"Had I invested the money instead, I could have comfortably retired now (I am 44)," he writes.

You'll likely spend your 30s in a senior position that requires significantly more time and energy than your job did in your 20s. For the sake of your well-being, you should be vigilant about scheduling time specifically for your family and friends. The fulfillment you can gain from keeping loved ones close will keep you happier and more productive.

"Don't just work," writes Microsoft product designer Michael Dorian Bach, who is now in his late 30s. "Make memories. The older you get, the harder it is to make meaningful relationships. Foster those while you're young."

Entrepreneur and blogger James Altucher, who is now 46, writes about a particularly difficult memory for him: "When I was 34 I hung up the phone on my dad in an argument and never returned his calls. Six months later he had a stroke and died. A week before that he had emailed me to say hello but I didn't return the email. I'm sorry, Dad."

It can be easy to forget that your parents grow older as you do. Don't take them for granted.

Bach writes that the pursuit of a career can also be a drain on one's health. "Be healthy. That is priority No. 1. Don't get into your 30s being slow and tired all the time. It sucks," he says.

Do what you can to stay healthy: Exercise, eat right, limit your vices, and take care of your mental health.

There is not, of course, a correct time to have a child. But one of the most recurrent regrets among people writing in the Quora thread was waiting too long to start a family. Regardless of family structure, they agreed that your 30s are a good time to make a decision if you want to raise kids or not.

CEO coach Alison Whitmire, now 44, writes that only after she became a mother did she realize that her fear of not being ready to have a child was unfounded, since no one is ever adequately prepared to have one for the first time.

Just because you're not in your 20s anymore doesn't mean you need to give up enjoying life. Bach says he spent the early half of his adult life chasing money, and it only made him unhappy and more cynical about life.

Go on dates with your significant other. Take your kids on trips. Go to concerts with your best friends. Just don't forget that the money you work to make is useless if you're miserable.