How are you replenishing it? Personally, I always take bets, even at long odds if I know they are in my favour. No professional ever offers that, no matter how it sounds. Richard Feynman liked to visit Las Vegas, and he heard of a guy who was famous for living as a gambler. When he got a chance, he braced him for a math-based explanation. It was very simple. He never bet on the house games. He bet with the people privately, making side bets on the roulette wheel, etc. according to the real odds vs what they were expecting. If you have a head for card-counting, that might be a feasible profession, but even the very best have had loosing streaks the price of a house.