1. Some friends aren't worth your time.
As your life and priorities change, you're going to realize that some people just don't fit in anymore. Maybe she still goes out like you guys did in college. Maybe you find you don't have anything to say to each other anymore, even on Gchat. You probably feel like you barely have enough free time as it is, and some people just aren't worth it. Smile at your good memories, but know that it's OK to move on from the friendship.
2. But make time for the people who matter.
Between work and exercise and your boyfriend and Netflix, it's hard to find time for yourself. But it's also important to carve out face-to-face time for the people in your life whom you really care about, IRL, not just texting for an hour straight.
3. It's simultaneously harder and easier to make friends in adulthood.
You know exactly what qualities you want and don't want in a friend now, so it takes a lot longer to find people who are truly worthy of your time and who you trust when you start a new job/move to a new place/try a new activity. But since you DO know exactly what you want, you become super-close super-fast with those great people when you find them.
4. You'll have fewer friends by the end of your 20s, but they'll be great ones.
Your friend group will inevitably shrink as you age: Some friends will move away and be bad at staying in touch. Some will get absorbed with their jobs or families. Some will just not be right for you anymore (see No. 1). But the old friendships you keep will get even stronger and richer, and the new friendships you start will be incredible (see No. 3).
5. There's no best friend like your childhood best friend.
She's a sister without the family drama. She'll also never let you forget about the time you thought you were talking to a James Van Der Beek lookalike in a chat room in 1997.
6. Some friendships will require more effort than others.
You may think that a text here and there and an in-person date once a month constitutes adequate committment to a friendship, and for some people that is the case. But if a friend you value thinks a relationship requires more than that, make the effort to meet her at least in the middle.
7. You don't have to be friends with your boyfriend's friends or their girlfriends.
But you should be able to get along.
8. People are going to be horrible to you, even after high school.
Some people, even adults with jobs and marriages and kids, still get their kicks from being mean to people. Some people will change as they get older and value your friendship less. The advice is the same as middle school — don't engage, move on — but now you're mature enough to follow it.
9. If something a friend is doing is really bothering you, talk about it.
It's obviously hard to confront a friend, but there is no way any negative situation will get resolved by doing nothing or by being passive aggressive. She may have no idea she's upsetting you and your relationship will come out stronger, or she may be fully aware and it's time to let go of the relationship. On the flip side, if a friend comes to you wanting to talk, listen and respond.
10. Your mom really can be your best friend.
She was probably right about that one.
This article originally appeared on Cosmopolitan.com. Minor changes have been implemented by Cosmo.ph editors.