How many stacks is still ok to lose???

I'm getting pushy. I've taken to heart the advice "Push" given so often in these posts. No regrets. My game has improved.
However, ( there's always a however), be that as it may, sometimes I LOSE MY STACK!!
What is an acceptable level of losses in this manner?
Wins should exceed losses...duh. This is not really helpful, because any one run of cards will distort any "average" that one might refer to.
What benchmark might i refer to , so see if i am now playing too loosely?