I think many gamblers set "double deposit" as their minimum goal. Even though those who gamble for fun, when they double their deposit, they start to think about making a withdrawal. I look positive on having such goals. And there those who "wont leave until they get a high multiplier or win jackpot". Such kind of goals I dont recommend anyone to have. Gambling without a goal, that is a rare thing to see today. I rarely see those who prefer gambling as a time killer.
It seems to me that those who play for fun will not withdraw their deposit. Even if they set a goal for themselves like doubling their deposit they will not cash out. When they reach that goal they will just set a new one and keep playing. And those who aim to hit a jackpot will probably not withdraw either no matter what goals they achieve. It reminds me of traders who can turn small amounts into millions and then a few weeks later go back to zero. It is a kind of submission to excitement that is very hard to escape. You always want more and more. So if you don't set a clear goal for the amount you are going to withdraw most likely everything you win will stay in the casino and eventually turn into losses.