Most carts are not lost.
They are paused. Remind people, at the right moment.

1. 1
   A cart is started

   The email is known once checkout begins.

2. 2
   Left on the checkout page

   No order after a set time.

3. 3
   Three reminders

   1 hour, 24 hours, then an optional offer at 48 hours.

4. 4
   They come back

   One click restores the cart; the reminders stop.

5. 5
   Or stock is released

   No endless emails, held stock goes back on sale.

Timings and the offer are an example. Reminders only go to shoppers who agreed to receive emails, with an unsubscribe link in each one.