The wagering requirement is the main factor. For example you get a $100 bonus with a 30x requirement. That means you need to place $3,000 worth of bets before you can withdraw. Game weighting is just as important. It dictates how much each bet counts. A $10 spin on a slot that contributes 100% gives you $10 towards wagering. That same $10 bet on a game with a 10% contribution only equals $1. Also pay attention to time limits, maximum bet rules while the bonus is active, and lists of games you’re restricted to play.