One of the first decisions you'll make when setting up a loyalty programme is your reward threshold — the number of stamps a customer needs to collect before they earn a freebie. It sounds simple, but getting it wrong can quietly undermine the whole system.
The psychology of progress
People are motivated by progress. A stamp card with six slots feels achievable. One with twelve feels like a marathon. The sweet spot is a threshold where customers can see the finish line from the start — close enough to feel attainable, far enough to be worth your while.
Research into what psychologists call the "goal gradient effect" shows that people speed up as they approach a goal. A customer with five out of six stamps will visit sooner than one with two out of six. This is why giving a starter stamp — one free stamp just for signing up — is so effective. It puts the customer on the board immediately.
The numbers behind the decision
Let's say your average coffee costs three pounds fifty. If your reward is a free drink and your threshold is six stamps, you're giving away one drink for every six purchased — roughly a 14% discount. At eight stamps, it's closer to 11%. At ten, it's 9%.
That might sound like a small difference, but at scale it adds up. A shop serving 200 loyalty customers per week at a six-stamp threshold is giving away significantly more than one at ten stamps.
But here's the catch: a lower threshold means more frequent rewards, which means more frequent dopamine hits, which means stronger habit formation. The question isn't just "what can I afford?" — it's "what drives the most return visits?"
What the data suggests
From the patterns we see across merchants, the most effective threshold for independent coffee shops sits between six and eight stamps. Here's why:
Six stamps works well for shops with daily commuter traffic. These customers visit frequently, so they complete cards quickly and stay engaged. The faster reward cycle keeps the momentum going.
Eight stamps is the sweet spot for most independents. It's achievable within two to three weeks for a regular visitor, which keeps the goal visible. It also gives you a comfortable margin on the reward.
Ten or more stamps tends to cause drop-off. Customers lose interest or forget about the programme before they reach the finish line. Unless your average customer visits daily, ten stamps feels too far away.
Don't forget the starter stamp
Whatever threshold you choose, consider giving new customers a free first stamp when they sign up. This does two things: it creates an immediate sense of progress, and it makes the remaining stamps feel more achievable.
A card that shows "1 of 8" feels very different from one that shows "0 of 8." That one small gesture can meaningfully increase how many people complete their card.
You can always adjust
The beauty of a digital loyalty system is that you can change your threshold without printing new cards. If you start at eight stamps and find that completion rates are low, try dropping to six for a month and see what happens. Track the data, look at completion rates, and let the numbers guide you.
There's no universal right answer — it depends on your prices, your margins, and your customer behaviour. But with the right data, you can stop guessing and start optimising.