The bonus advertised on the front page is rarely the bonus you actually get. Wagering requirements turn a flat percentage into a probability problem — one that, in many cases, has a negative expected value.
The formula
Effective bonus value = bonus amount × (1 − wagering × house edge). For a 200% match of €100 at 60x wagering on slots with a 3.5% house edge: 200 × (1 − 60 × 0.035) = 200 × −1.1 = −€220 in expected value. The bonus is worth less than nothing.
What 'good' wagering looks like
Anything below 35x is acceptable on slots. 25x or less is good. Anything above 50x is a marketing prop, not a real offer. Always read the max-bet clause too — bonuses are routinely voided for stakes above €5 while wagering is active.
Bonus expiry windows
A 30-day expiry is normal. A 7-day expiry is a trap — you'll either chase losses to clear it or lose the unspent balance. Walk away from short windows.