When a player goes all-in, he or she bets all of their chips. All-in bets may be placed in any betting round, including the preflop. The following scenarios call for an all-in in No-Limit Holdem:
You have the “premium” hand in your possession. All-in bets are best made on the Turn or River since late-game opponents are less likely to call.
You’re holding an excellent hand. Raise the stakes on the flop if you have excellent odds of making a winning hand combination. It’s a good idea to go all in if your opponent makes a hostile call.
You want to bluff but you have a terrible hand. Although going all in with a bad hand is a common movie plot point, it’s not a strategy you should use until absolutely necessary.
You’ve it it thus far in the tournament and now have the largest stack. You make an all-in bet, including the blinds and ante, knowing that your short-stacked opponents would call or raise to remain in the game. Large stacks encourage aggressive play, whereas short ones encourage a more cautious approach.
On the other hand, your opponents may decide to go all in as well. The prudent action here is to examine your hand; if you have a strong hand, calling is a good idea, but folding is preferable if your hand is weak. In the event of a multi-player all-in, the stack is divided proportionally among the winners based on the number of large blinds in play and the quality of their hands.