Make sure you check the payout table to find out. The payout table is a small printed sticker displaying the percentages of likelihood for the winning combinations. If you don't want to pay the maximum, consider finding a less expensive slot machine.
Casinos use a random number generator (RNG) to determine when a slot machine will pay out. The RNG ensures that each spin is independent and not influenced by previous spins. This means that there is no way to predict when a slot machine will pay out, as each spin is purely random.