Do you just stop caring for some friends?

Yes, this happens. Sometimes you "outgrow" people, sometimes you just had a job in common and when one of you moves on there's not much to talk about.

Relationships need regular relating..

If the person is not in your life and thus is not relating to you on a regular basis then yeah the relationship can fade away to nothing..

It takes constant effort to keep a relationship.. That effort means keeping regular contact..

I do have former friends who I've moved on from, for a number of different reasons. Usually it's because we've grown apart and really don't share much common ground. I also tend to shy away from people who create drama, or are very emotionally needy.

I think some friendships have shorter roads. I don't think that means you can't stay on good terms though.

I always remember and understand why a friendship started and I can pretty much realize why a friendship ran it's course... usually because there is nothing much in common after a while...sometimes many years or just a few.
I don't stop caring and often wonder how those friends are, but realize it wouldn't be wise to start enquiring and have it be a strained conversation which will go nowhere.

yeah. people outgrow each other, sometimes

I don't think we stop caring, but I think it's normal for friends to drift apart.
I have a handful of good friends, but some abandoned our friendship when things went haywire with my family.

Yes happens a lot. 🤷‍♀️

It happens. Sometimes people connect from shared circumstance and then when the circumstance ends (like work or school) they drift apart.

Sadly, that happens. I still care about them, but there are friends I’ve outgrown, especially those from my "clubbing" days.

Yeah, it happens

Yes,even with family. Some people are too toxic to keep in your life