How many stamps should a card have?
Six is too few, twelve is too many, and the right answer depends on how often people already come in rather than on what the reward costs you.
The number of stamps on a card is usually picked by feel, and the feel is usually “ten, because that is what everyone does”. Ten is often right. It is right for a reason that has nothing to do with round numbers, and once you know the reason you can tell when it is wrong.
The rule underneath it
A card works when a customer can finish it before they forget about it.
That gives you an actual formula, and it uses a number you already know:
Stamps ≈ visits the customer already makes in six to eight weeks.
Six to eight weeks is roughly how long a goal stays live in someone’s head without a reminder. Longer than that and the card stops being a goal and starts being a piece of admin.
Working it through
Take the visit rate first, then multiply.
| Trade | Typical visits | Sensible card |
|---|---|---|
| Coffee shop | 3× a week | 20–24 |
| Bakery | 1× a week | 6–8 |
| Takeaway | 2× a month | 4–6 |
| Barber | 1× every 4 weeks | 3–4 |
The coffee number surprises people. A daily regular hits ten stamps in under a fortnight, which means the reward arrives before they have changed any behaviour — you have simply given a discount to someone who was already coming.
When to go shorter than the rule
Three cases, and only three:
- A brand-new program. A short first card buys you proof that the thing works at all. Lengthen it on the second cycle.
- A trade with long gaps. A barber on a six-week cycle cannot be given a ten-stamp card; that is over a year, and nobody finishes it.
- A seasonal push. A deliberately short card with an end date is a different instrument, and it should look like one.
What the reward should be
Not the cheapest thing you sell. The reward is the whole reason the card gets carried, and a customer who does the arithmetic on a 40p reward will stop.
The useful test: would you mention it out loud at the counter? “Tenth coffee free” passes. “5% off your eleventh visit” does not, and no sign will save it.