1-2 hours or until i reach my target it depends of my luck..sometimes going down and crash. But in another day it doubles or it keeps on crashing - 
Same goes for me here dude. As long as i'm winning then im playing. Also depending on the gambling type. Usually i get easily bored with games like dice. Once i lose one or two times there i lose interest already. But if i'm playing poker, or roulette, then it may take hours before i leave the table. Some gambling games are just much more enjoyable than others