Yes and no.
I am friends with most. We were kids when we were together and very much not right for each other, there were no hard feelings really, and we still have some things in common. I am not super close to either of them, but we are on friendly terms, occasionally exchange correspondence, hang out, etc. There is nothing unhealthy about it. The past is way in the past, and we are comfortable just being friends.
Others I have lost touch with. I would be happy to be friends with them if our paths ever cross again. Again, amicable break ups/parting ways, no hard feelings, and I’m sure we’ve all moved on but still have some things in common. There is one I don’t think I have anything in common with and I don’t think we will ever really be friends, and that’s fine.
One I am not friends with, do not speak to, and am not sure I want to ever see again. This guy was an immature, inconsiderate, selfish, conceited douche bag and, while I have forgiven and moved on and understand both that he probably just didn’t know how to handle himself and that we were so not right for each other, he left a really bad impression.
My current bf I could definitely see staying good friends with if things went south. I think when you get older, you do a better job of picking compatible people to be with because you know yourself better and you know how to know other people better, and hopefully communication is more open and mature with less destructive drama. I think this makes it easier to stay friends.