Glossary
Rollover
Rollover, also called playthrough, is the total amount you must wager before a promotional bonus can be withdrawn as real cash. A bonus with a high rollover requirement forces you to bet it many times over, and the vig on each bet steadily erodes the value along the way.
A bonus is rarely cash you can simply collect. Rollover, sometimes called playthrough, is the string attached: the total volume of bets you have to place before the promotional funds turn into money you can withdraw.
The requirement is usually written as a multiple. A hypothetical bonus might carry a 10x rollover on a stated amount, meaning you must wager ten times that figure before anything unlocks. On a modest bonus that can add up to a large amount of required betting, and every one of those bets is exposed to the house margin.
Why the vig matters here
Each wager you place gives up a slice to the vig. Grind a bonus through many turns of rollover and those slices compound, so the cash you can eventually withdraw is typically well below the bonus's face value. The higher the rollover and the higher the odds you are forced to bet, the more the expected value of the offer shrinks.
Read the terms as math
A big headline bonus with a steep rollover can be worth less than a smaller one with an easy requirement. Look past the advertised number to the playthrough multiple, the minimum odds, and any time limit before you judge whether an offer is actually worth chasing.
Treating rollover as a real cost, not a technicality, is how you decide whether a promotion helps you or just keeps you betting.