The all-in bet is used both by players with a strong hand to take as many chips from an opponent as possible, and by players with a weak hand to force an opponent to give up. The technique is also used in some poker strategies: for example, in the “push-fold” stage, where preflop a player with a small stack either folds or plays for all chips. All-in is often used in two cases: the hand is strong and you need to increase the pot , or the hand is weak - and you need to force your opponent to throw away the cards.There are other situations as well. Let's say you're on the pre-final table of a major tournament and you've got a good stack. Then opponents with short stacks will try to "sit out" to wait for others to fly out. It is appropriate to play all-in against them - few people want to take risks before the final table, so the blinds and antes will go to you.