How we decide a code is dead
A stated expiry date is the weakest signal we have. Here are the three we trust more.
Merchants change codes without announcing it far more often than they let a stated expiry lapse, so a date on a coupon is a hint rather than a fact.
Shoppers telling us it failed
Someone who just tried a code at checkout knows before any statistic does. A handful of reports is enough for us to re-check by hand.
People revealing a code but not continuing
When a code gets copied often and almost nobody goes through to the merchant, the code has usually failed visibly on the page.
The stated date, last
We still hide a code the moment its stated date passes. It is simply the signal that arrives last.