Two jobs, not one
Retention and win-back sit at different points in the lifecycle. Retention keeps users who are still active engaged and getting value. Win-back — sometimes called resurrection — targets users who have already lapsed. Amplitude defines a resurrected user as a previously inactive user who returns. Conflating the two leads to nagging active users and ignoring the ones actually slipping away.
Set the trigger to your cadence
The dormancy threshold that should trigger a win-back depends on how often your product is naturally used. A daily app might consider a user dormant after one to two weeks; a monthly tool, not for several weeks longer. Picking a window that matches the cadence is the whole game — too short and you pester active users, too long and they're gone before you reach out.
Keep it short, then suppress
A typical win-back is two to four messages: a soft we-miss-you check-in, a reminder of the value or an incentive, and a last-chance confirm-you-want-to-stay. Short is deliberate. Repeatedly emailing people who don't engage hurts your sender reputation, so non-responders should be suppressed — removed from the active list — which also keeps your data and consent posture clean.
Measure real returns, not one-time clicks
Don't judge win-back by the reactivation click alone. A user who opens once and leaves again isn't won back. Track retention at 7, 30, and 90 days after they return, so you can tell a genuine resurrection from a one-time bounce. Segmentation helps here — grouping users by how recently and often they engaged tells you who's worth a win-back at all.