There isn’t just one correct way to play a slot machine. If only have a $20 bankroll for the day and you just want to stretch your playtime as much as possible, then betting less will help make that last longer. For instance, if you really like playing slots and don’t want to mess with changing machines every few minutes or getting up and down to push buttons, then it might be a good idea for you to place the max bet on whatever machine you find yourself on.