If you want to direct your anger at other posters for calling you a "ploppy" and trying to convince you to count cards, go for it, but spare me the trouble. I'm trying to explain to you why your question can not be answered in a logical way. I don't care if you're an advantage player, an average civilian, or a system player. I also don't care how much you've won or lost. The problem is that your question is straightforward, but the answer is not.
Straightforward question: If I have x amount of money and I win y amount, how much of y should I be willing to lose before calling it quits?
Sounds like a simple question, right? Well, it's not! And the reason it's not is what I've been trying to explain, and what you've chosen to react negatively to each time. Unless I misunderstand the question, you seem to be asking the optimal point at which to stop playing in order to maximize the "profit" that you somehow expect. I will attempt to give you the straightforward answer that you're looking for if this is, in fact, your question:
1. Are you an advantage player? Do you have a statistical edge over the house? If so, the answer is that you should never stop playing unless the game conditions change, rendering your advantage to a less desirable, or nil, amount; if you're receiving heat or attention that may threaten your longevity; if you're too fatigued to maintain the edge that you're playing with; if your bankroll has taken such a hit so as to either require smaller wagers to stay within an acceptable amount of risk or put your in an emotional state that compromises your edge; etc.
2. Are you playing without a statistical advantage? This includes non-composition-dependent betting strategies, hunch players, random gamblers, and the like. If this is the case, the optimal stopping point would be the point immediately before you sit down at a table game and give a dealer money. I'm not being a smart-ass here, but it's a simple fact. I know you fall into this category because you're asking about how long you should play with the "house's money," when in fact, there is no such thing. Any money you win is yours, and any money lost is now theirs. If I'm wrong and you're playing with an edge, then it doesn't matter when you need to stop, you'll still be making money.
I was playing a game yesterday that involved betting two hands of one unit each. After a long and painful stretch of having my ass handed to me repeatedly, a situation occurred that caused me to have all of my remaining session bankroll on the felt at once, totaling four units. I had a positive expectation on the outcome of all four wagers, but should I have stopped before that? Of course not, because it was optimal to continue betting as long as I had the edge. If instead of being down to my last four units, I was instead up 40 units, should I be concerned with a stopping point?
I know it's unlikely that you'll find this reply useful or helpful, but I hope that you'll eventually realize that I'm answering your question exactly and as in-depth as you're likely to get. Whether or not you choose to try and understand what I'm saying is your choice.
