Hit frequency is the share of spins that return any win at all, and games often publish it in their help pages. A figure of one in four means that, on average, three spins out of four pay nothing. Many of the wins counted are smaller than the stake, so a hit does not always mean profit on that spin. A high hit rate keeps a balance moving slowly, while a low one lets it fall in longer steps between payouts.
Many slots cap the largest win a single spin can produce, often as a multiple of the stake. Once the cap is reached, the round ends and any further winnings are forfeited, which trims the top of the payout range. Games that sell entry to their bonus round list a separate return for the bought feature, sometimes higher and sometimes lower than the base game. Both figures sit in the help pages or the rules, and both change what a large stake can realistically return.
Measured returns drift away from the theoretical figure over any stretch a person can play, and the gap narrows only across millions of spins. Tracking sites that pool results from many players show this clearly: a game can run far above or below its figure for weeks. Demo modes normally use the same maths as real play, so a free session shows the rhythm of a game, although a short demo run says as little about the true return as a short paid one.