Stance
A new customer is at peak engagement immediately after opting in. Maximise this window.
In practice
The first message must deliver on whatever the opt-in promised, whether that first contact is an email, an SMS, a push, or an in-app prompt. Failing here erodes trust before the relationship has started, and it is the most common own goal in onboarding. The mechanics differ by channel, an email welcome runs as a multi-step sequence where SMS is a single high-value send, but the window and its decay are the same.
Do not lead with a discount
Opening the welcome with a discount trains customers to game the system and attracts the wrong audience.
See automation and sequences and list building.