Wagering requirements are simply the amount of times you need to wager the bonus funds at the casino before those funds become eligible for withdrawal. For example, a 35x wagering requirement on a bonus of £100 will require you to wager that money 35 times. In other words, if you’re playing slots, that would be £3,500 worth of spins. Often this is more achievable than it seems if you play sensibly with low variance games.