Small stacks
When you have a small stack you can’t afford risking chips on average hands. The opponents with larger stacks will be able to call you down no matter what they’re holding, without risking a lot. This means that “The Gap” (see “Tournament theory – the cap concept”) is considerably smaller in these situations. What you want is a really strong hand to move all-in with.
Large stacks
When you have a large stack you should use this to take control of the game. Stealing pots through raises becomes much easier, especially when the stakes are high. “The Gap” is obviously bigger when you have a large stack.
Middle stacks
Middles sized stacks are more difficult to handle. Your goal is to become a big stack but if you take too many risks you might become a small one. When you’re in this situation you should try to play more hands against the small stacks, and fewer hands against the big stacks.