When you realize your not compatible with that person.
That is tricky because sometimes it is not the other person that causes conflict --but only your perception of that person. So if you write someone off, you may just be giving into your own weaknesses. Strong people should not need to write anyone off because they are not scare by people's effect on them. Sometimes we can learn important lessens in unexpected places. So take care of yourself, but don't make assumptions about others.
This is true, except in those cases where those so called friends can not accept that you may differ in your opinion, and do no work to try to understand your opinion but instead call you out as being opinionated, when it's actually them who's opinion will not bend.
That is true.
When the other in the relationship no longer makes you feel relevant. With any relationship we want to be heard, we want to know our "friends" remember important events and milestones in our life. When interest in us ceases, it's time to end things as the benefit of the relationship doesn't exist; and if honest, it brings us down instead of lifting us up.
When being with them is more painful than being without them...it's always sad and it never resumes....gotta let it go
I think when ever someone is doing/asking more for their benefit then yours, the clock has struck it final toll.
Having said that. We should accept people for who they are, but we don't have to continue to deal with their BS.