I think many of us do, RTR Risk to Ruin ratio, how much are you willing to risk and what is the amount that will ruin you as I like to think of it.
Hear are my session rules ... I never sit down at a table if I don't have over 40 hands worth of cash to play with. $ 5 table min. bank $ 200, $ 25 table min. $ 1000
you get and idea. If and I lose half my bank it's time for a break and look for a different table of lesser value or end my session for the day.
Next day session I take the remainder of my first day and add it to my second session making my bank whatever % larger. Then the same rule applies if i lose.
food for thought
by: spincycle59
If you quit after losing half your bankroll, then your bankroll was half of what you started with.