The bankroll

Your bankroll is the amount of money you set aside to play poker with. Some players can easily deposit more money while others have not been as easy to replenish the bankroll of money would be lost.
It is extremely important that you do not play at levels that exceed your bankroll. A good guideline is that you must have a bankroll of 30 - 100 times the maximum purchase. Bank roll should also be money that you can lose without concern yourself too hard. You then can afford to lose some without affecting your game.
The players who are professionals like to have more purchase than that. A large bankroll can counteract tilt because capital does not move as much by losing one or two purchases.
A large bankroll in proportion to the efforts have also status and self-confidence and can make the second easier to bed instead of calling.
They think that they are all about the little money on the low tables, and instead goes up and play with pretty much everything they have. Often this ends badly, sooner or later.