So, I’m there: I’ve made it to my thirties. It wasn’t scary; It wasn’t sad. It just was. Because, really, there’s not much difference between being 29 years and 364 days old and being 30 years old. But, I will admit, there is a major difference between how I dressed throughout my twenties and how I dress now. To help you avoid these same mistakes, I thought I’d compile my (hard-learned) wisdom of age (“age”).

1. Don’t buy a size you’re dieting to be someday.

Oh wow, my closet is full (well, half full) of clothes that I fit into for like one really good, super skinny, pretty dehydrated day. I mean, I won’t get rid of them because I still have a goal weight (just like everyone does, right?), but I could have saved a chunk of money if I had just been more realistic about my dieting practices—and bought shoes instead! On this note, don’t try to squeeze into a size you aren’t. It more often than not results in a squeezed sausage effect that no one likes. Or wants to sleep with.

2. Buy less for more and wear it longer.

I, like many women in their twenties, worshipped at the altar of Forever 21 throughout most of the decade (and even Charlotte Russe in high school. Remember that store?). But, what I should have done was put money aside from each paycheck, just a little, and saved up to buy one nice, pricier item every 6-12 months, then filled the rest of my wardrobe with less expensive basics (casual shirts, jeans and flats, always, from Gap or Banana Republic) each season. After a couple of years, you end up with some envious pieces, a killer wardrobe and a distinctive style. Just saying: Put down the floral crop top that will shrink to the size of a onesie after a single wash. It’s not worth your $3.

3. Stand up straight.

There is nothing that bugs me more looking back at pictures of myself from a few years ago, when I was actually wearing a cute outfit (or hell—my WEDDING DRESS) and wished someone had told me to stand up straight. I know I look about 5 pounds heavier than I actually was just because I didn’t notice I was slumping my shoulders. Important advice from my ballet teacher: Pretend like there is a string running up from your spine through the top of your head and pulling you straight up to the sky. It works. Do it, younger me.

4. Be bold.

I spent so long being scared to wear anything that was too brightly colored, or too voluminous, or too structured, or too has-a-crazy-print. I should have just taken the plunge and worn those super fun clothes because, I promise, no one is judging. (OK, some people might judge, but they’re boring anyway so who cares what they think?) It’s not that I was young enough to take fashion risks and I’m too old now that I’m 30; it’s that I feel confident being bold just now, when I should have always been—I could have looked way cuter way earlier.

5. It’s OK to dress up when no one else does.

This one I actually figured out a few years ago, before I was done with my twenties for good, and it’s a useful lesson. People will look at you weird (with the side-eye) for being underdressed, but they will be envious of your confidence if you’re overdressed. Nothing wrong with it.

6. Keep your shoes and purse in top shape.

This is a lesson for which I can thank my mother, who has always been full of fashionable advice. Particularly when you’re going into an important meeting, like a job interview, which will happen often in your first decade out of school—you should be acutely aware that you are being judged on your looks. Obviously, you’re also being judged for other things, like talent and hard work, but you won’t get far if you don’t look polished. Whether or not that’s how it should be doesn’t matter—that’s how it is. So suck it up and buy new heels, whether or not you want to.

7. Shop your budget.

Don’t spend yourself into debt. That handbag you’re in love with now that will cost half your rent won’t be as special next year while you’re struggling to pay off your credit card bill. Seriously, walk away.

8. Don’t wear a jean skirt. EVER.

All of us—ALL OF US—are, at any given point in our twenties and probably most of our teens, too old to be wearing a jean skirt. Especially if it’s a cutoff. Have some self-respect, ladies.

9. Wash off your makeup every day and use a face lotion with sunscreen.

It only takes a few extra minutes at the end of the night, and you can even do it while wasted on a Saturday evening! You won’t see the effects of your good habits for a few years, but I promise, the time spent is worth it. Oh, and while I’m here, another piece of beauty advice: Quit smoking. Yes, being a “social smoker” is still terrible for your health. And maybe go to yoga once in a while.

10. You don’t have to look perfect all the time.

You don’t. You really, really don’t. This is a huge perk of living in Los Angeles, that most people are casual and the uniform de rigueur seems to be nice sweats. I especially take advantage this on Sunday mornings at brunch: yoga pants, sunglasses and a hat. Can’t miss.

11. Choose a signature piece.

Oh, this is my favorite. Each year, I put some extra cash into a nice, noticeable necklace. The last two years have been big and chunky and have come with endless compliments.

12. It’s OK to make fashion mistakes.

Because, the worst thing that happens is in 10 years (or sometimes two), you look back and laugh. Seriously, the fashion police aren’t an actual thing—no one will send you to jail.