Leaving a small balance at the time of withdrawal is something I'm used to. And it has indeed become a habit for me to come back the next time, or even the next day. I usually set a winning amount, for example 1x, or 2x, or whatever from the amount of deposit I made. I do that to suppress my greed if I have tasted victory. As you said, we don't know when we win whether the luck is still with us or has left, so we have to keep something so that our initial victory is not lost just like that. It would be a shame when we have won, then we can't withdraw anything from the casino.
I also leave a small balance, maybe $10 to $20, in the betting account so I can get back to gambling whenever I want. And we can come back at any time because we have found pleasure in playing that gambling. But I never set a limit or win amount because it's hard for me. So if I win at any rate, I will try to stop immediately instead of continuing to play gambling in other gambling games because that can trigger the defeat that I will receive. It can also avoid frustration if I stop because by continuing to play to reach the win limit and we lose, we can become frustrated and want to keep playing until we reach the win limit.