While a bonus is active, most terms set a maximum stake per spin or per hand, often a small fixed amount or a share of the bonus. A single bet above it, even by accident, can be enough for the casino to remove the bonus and its winnings. Some games let the stake be raised mid session with no prompt at all, so the limit is worth setting in the game before starting. The rule usually ends once the requirement is met.
Many casinos keep cash and bonus funds in separate balances and spend them in a set order. Where cash is used first, a player can win and withdraw before the bonus is touched, and the bonus simply lapses. Where the bonus is used first, or the two are merged, every win stays locked until the requirement is complete. A progress meter in the account shows how much turnover remains, and it is the quickest way to see where a session stands.
Some titles are excluded from bonus play altogether, often slots with a high return or with features that could be used to clear a requirement cheaply. Playing an excluded game with bonus funds can void the bonus and every win attached to it, even when the game loads without any warning. The list usually sits at the end of the bonus terms or on a separate page. Checking it before the first spin avoids losing a balance to a rule nobody mentioned anywhere in the lobby.