Spots to use the All-in move
The All-in move is one that is highly effective if you can pick the correct spots to use it.
Mainly, when a player moves all of their chips or money in to the pot, they will have a hand that they are comfortable with, and one that they feel will win. At other times though, there are some players who will move all their money in with big drawing hands such as two over cards and a straight draw, or flush draws.
But to make a common rule of the all-in play, you will want to try and be as certain as possible that either your opponent will lay their hand down, or you will get a call and be ahead in the hand.
Playing a tournament and you are short stacked at the table with say ten big blinds left and you are dealt an ace high in the cutoff. If the table folds around, this is a spot to move all the money in and hopefully get folds. Although, you are not happy to be putting your money in with just an ace you will have to make that type of move to hopefully get folds, or get called and get lucky in the hand.
In a cash game, a perfect spot to use the all-in play is with a huge flop like the nut flush draw or even if you flop bottom two pair to protect your hand from a scary board.
Putting your opponent to the ultimate test of will power is what you want to accomplish by shoving your stack in the middle. When you can put your opponent to a big test in a situation where you are even money on the board is when you want to shove in.
Most of the times depending on the situation you will get folds from better hands, and the other times when they do call, you will have an opportunity to win the pot by outdrawing your opponent. So, you can put all your money in with a big draw, or to protect your hand on the flop ideally.
Lastly, a spot to put all of your money in the pot would be with a monster hand on a scary board like a set on a board with three cards of the same suit on it.
If you check and then make a big shove on your opponent for all their chips if they have the nut flush draw with a pair they will more times than not look your hand up for their stack. A lot of players have trouble with laying down the nut flush draw in situations like that because they feel that they have outs to win the hand which is true, but they are also a big dog to win the pot unless they hit their out.
Even if they hit their out on the turn, they still have to dodge a river that you will have most likely a minimum of 9 outs and sometimes 10 outs to draw to. Putting your opponent to a big test is what the All-in move accomplishes, and something that you should look for when playing cash games and tournaments. The only difference being that in cash games you can reload your stack, and in tournaments you cannot, so pick your spots wisely, and hope it turns out for the best.