The question "What is a wagering requirement?" usually comes up after a bonus has vanished, taking its winnings with it. The cause is almost always a condition in the terms: a deadline that passed, a withdrawal made too early, a cap on winnings or a clause about irregular play. Each of these can be seen in advance, and a few minutes with the terms show which of them apply to a given offer.
Requesting a withdrawal while a bonus is active often cancels the bonus and everything won with it, and some casinos apply the rule even to cash deposited alongside it. A player can usually cancel a bonus on purpose from the account page, which frees the cash balance at the cost of the bonus. Knowing where that option sits, and what it removes, turns an accidental forfeit into a choice made with open eyes.
Many bonuses limit how much can be withdrawn from winnings made with them, often as a multiple of the bonus or a fixed amount. Winnings over that limit are taken back at conversion, even after the full requirement has been met. The cap is easy to miss because it appears in the general terms instead of the offer page. On a small bonus it can make a large win on a volatile game worth only a fraction of its face value.
Every bonus has a deadline, and usually two: one for claiming it and one for completing its wagering requirement. When the second passes, the bonus and any winnings still tied to it are removed, however close the requirement was to completion. Deadlines range from a day for free spin winnings to several weeks for a large match. The clock often starts at the deposit, which means a slow first session already uses part of the time available.
A saved copy proves which version of the terms applied on the day the offer was taken, which matters if the casino later changes them.
Usually from the account page. Doing so frees the cash balance but removes the bonus and whatever was won with it.
The bonus and any winnings still tied to it are removed, however close the requirement was to completion, and the clock often starts at the deposit.
Casinos can revise their terms, though most promise that a bonus already claimed stays under the version the player accepted at that time.