So a lot of people recently (coincidentally) keep hitting me up and making chitchat, and then it turns out that they need something from me when otherwise they don't really care about me. Is it better to bring this up with them or just accept it and move on?
Accept that they are dicks and stop hanging out with them or spending time with them.
Don't be a doormat. Spend your time around people who are actually worth it -- people who want to spend time with you because they actually like you, and not because you're convenient for them.
>having friends
Seems like a pretty common thing to me. If what they need isn't inconvenient, I don't think it matter much.
If they're leeches you can just start random conversations and spam them when they don't reply.