I always do this. If I made a profit with my deposit I only play with the profit. This the way I like to play most of the time.
By doing this I know I am not going to lose a lot of money because I only make one deposit each time I play.
Everyone has different method but for me I don't consider it as a profit yet if I'm still playing. I can only tell that for a day I'm profitable when I stop gambling and withdrew with a profit. I have a target to get and once I hit it already, I automatically stop and I'm able to follow my game plan for years already.