How many stamps belong on your card
The calculation that decides whether a card gets finished or forgotten, worked out from how often your customers actually return.
August 18, 2026 · 5 minutes
It looks like a detail. It is not. The number of stamps decides how long a customer takes to reach the reward, and that length is what separates a card that gets finished from one that gets abandoned halfway.
Start with the rhythm, not the margin
The temptation is to work backwards from what the reward costs you. That is the wrong first calculation. The first question is simpler: how often does a customer who already likes you come back.
An office coffee shop sees the same person four times a week. A dinner restaurant sees them every fortnight. A barbershop, every three weeks. With that figure, the stamp count stops being an opinion and becomes a division.
The six-week rule
In practice, a card that takes more than six or eight weeks to finish stops feeling reachable. The customer no longer associates it with their next visit but with a vague future, and a vague reward does not change behaviour.
Divide six weeks by your visit frequency:
- Someone visiting four times a week comfortably reaches 10 stamps.
- Someone visiting weekly is better at 6.
- Someone visiting fortnightly needs 4, or an intermediate reward.
When the number has to be high
Sometimes the margin does not allow a reward every six visits. The answer is not to stretch the card and hope: it is to split it. A small reward halfway changes the feeling of progress entirely.
A ten-stamp card with something at the fifth reads as two short cards, not one long one. The total cost can be identical and the completion rate is not.
What to watch after a month
Once the card has run for a few weeks, two numbers tell you whether you got it right:
How many get past the first stamp. If lots of people stop at one, the length is not the problem: you did not explain what they win.
How many reach the end. If most stall midway, the card is long for your real rhythm. Shortening it is easier than convincing anyone to visit more often.
What not to do
Do not change the length of a card people are already filling. Moving the goal mid-game is the fastest way to lose your best visitors. If you need a different setup, create a new card and let the old one finish its cycle.