It's widely accepted among players that the optimal times to play slots are early morning or evening, with peak hours typically occurring between 8 pm and 2 am. Take some time to watch the particular machine to gauge when it is most likely to pay out.
Typically, the more money you have to use to play, the higher the payout percentage is. For example, machines that requireR$1 or more generally pay out 95% to 99%, where 25 and 50 cent machines usually pay out 92% to 95%.