Cahsout? Probably "withdraw" word suits most for your question according to this thread. Well i saw many people doing that. I mean they withdraw money after big winning and keep a fair amount on gambling website so that they can start again with it the next day. I think this idea is wise enough for those who aren't professional but do gambling for entertainment. Because as you said, amount has high possibility to losse due to frustration or aiming even bigger amount to win. Although a responsible gambler always control his frustration, emotions and his mind, while gambling.
There are many gamblers withdraw their winning money after the big win they have but also we can not deny the fact that everyone of here in our community also know that once a greediness will take over the mindset of the gambler then if he)she will hit the jackpot still he/she won't stop betting cause he/she aiming more profits which is pretty bad habit cause we all know that not everytime bee put our bet we will win. So it's better to withdraw our profit before it will gone .