For me personally, there's no room for adjustment whatsoever. Even if I break out from the initial budget and wager on some games I may find interesting, and I win, it's a big loss to me. It's not about the money this time around, but about how weak I've become to lose up that easily for a game.
Also, it's one thing to Start the practice of always adjusting your budgets evertime, but its another' thing to stop when it becomes unnecessary. That's where the problem begins; the same tactics will miraculously becomes a nightmare.

well I can't say for some people, but the budget should be a determined by a person's pattern of income. If you love to gamble, Just check out for the spare you have left out after every other expenses, then schedule them through every week/month.