Suppose our bankroll is $100 and it has already grown to $500, would you quit or continue? Conversely, if with our bankroll, we are down to $10, would you still continue or save the remaining $10? I used specific amounts to make it easier to discuss this situation. I understand that we all gamble with different amounts based on our income, but consider this as an example. You can mention any amount you want based on your personal experience; it doesn't matter.
Making $500 from $100 is very good and I'll quit to gamble another time because I have already made 4 times more money so why would I be risking losing that money that I have made to get more. People who think that they can make more are greedy and they might lose everything including their bankroll of $100. If I was also down by $50 from the bankroll of $100, I'll stop and used the remaining $50 for another day. Losing 50% of my bankroll depending on how much was involved is my limit. Sometimes we mightn't be lucky when gambling and if we keep pushing it. It wouldn't make any different and we would have lost all the bankroll.