How do you know when to let a friendship go?

Friendship is not a matter of logic nor reason. So there is no formula with which you add up the points for and against, and continue until the balance goes negative. Friendship answers a human need of yours, and of your friend's.It is akin to love - the deepest well-spring of our happiness. It is not to be given up without a fight. It is finest when least deserved. It continues while the bond survives. It is too often lost by thoughtless inaction, by the need to overcome petty obstacles of time, availability and distance that life throws in our way. Losing a friend is a little death for our spirit. If we can continue in its warmth, by showing a little forgiveness, by overlooking small transgressions, it would be a small price to pay.