All plays
When to use it
When the page runs an evergreen countdown that resets on every visit, or 'limited time' claims with no real limit.
How to run it
Remove the fake timer or swap in a true recurring deadline, like an order-by shipping cutoff. Measure full-funnel conversion, not just clicks.
Why it works
Make it safe to believe you
Returning visitors who catch a resetting timer stop believing everything else on the page. The European Commission made Booking.com change misleading urgency and scarcity displays in 2019, and the FTC has flagged fake countdowns.
Source: FTC dark patterns; EC Booking.com ruling