You are right to set a spending limit because it is very tempting to play more and more and lose control of the situation. I once gambled online and my criterion was also to set an amount to spend, although I didn't always stick to it. When I realized I was losing, I tried to leave and try again later, with a cooler head and another stroke of luck. But it's always risky, because human beings like to break rules. Discipline is essential! Good luck to you!