There's not a 100% certainty that you will win either. You gotta have some luck with you if you're gambling.
that is what a lot of people think so. so when they start winning, they will start to bet bigger and bigger. that is when they start to lose, they will lose at a fast rate and even lose their capital.
Well I am not such a active gambling person, but I think it is easy for me when I am losing I stop guess. But when I win the dubble of money I have I spend the money that I won to play and I keep the money what I started to play with. This tactic only I do for Roulette or maybe Blackjack.