When is "Enough"?

During one of my sessions, my therapist asked me, "When is enough, enough?"

That question caught me off guard.

I mentioned that I don't want to quit especially when the going gets tough. I don't want to quit especially when I know I'm needed the most. I don't want to quit because I don't want to be known as a quitter.

She left it alone as long as I find ways to destress.

I thought the matter was resolved but it was brought up again by another person. 

Maybe I should seriously start finding the answer to that question.