Mine is evaluated based on how many of them were there for me when I was at my lowest. It'd be unfair for me to evaluate them based on communication, because then that'd mean that everyone would be gone, so that'd be unfair. I also don't think evaluating people based on what they gift you or do for you is adequate either. So, yeah, I think the clear line basis of me removing a friend is about sheer balance.
I don't like friendships that are just unrealistic. Where they want only and nothing but the best from you and for you. Friendships are about enduring someone's worst and figuring it through too. If you just push someone away all of the time and leave them in dormancy where their mind tends to wander into places it shouldn't. That's one of the worst things a friend can do and it can also include up to things like not talking to them just for a check up every now and then.
So again, if more friends have let me down or dropping the ball, then that's probably my reason.
Mine is pretty simple. If you do something with the intention of harming someone else (self-defense excepted), I will not be your friend.
If you are the aggressive, proud, vengeful or petty type, I’m not going to wait for me to do something that you find justifiable to use that same energy against me. If they did it to someone else, they’re capable of doing it to me.