When I was in middle school, I lived in T shirts and boxer shorts. It was definitely the style back then, and my mom sewed, so she would make me a ton of pairs. I was reading some fashion magazine, and it said to keep either your tops or bottoms solid, and the rest prints. That way you could mix and match your items more easily.
Fast forward 20-ish years, and that advice has stuck with me. It’s one of the things that I think about when I’m picking out clothes. Now, that’s not to say I never get a print pants, ’cause print pants are fun! I just think about it, especially when planning a mix and match wardrobe.