How many stamps should your loyalty card have?

Most small shops land between 5 and 12. Pick a number your regulars can fill in roughly one to two months: if someone visits twice a week, 8 to 10 stamps works; if they visit once a month, 4 to 6 is enough. Then check the reward costs you a small share of what they spend on the way.

Count the reward at what it costs you to make or buy, not its menu price. A free coffee might sell for $5 but cost you about a dollar in beans, milk and cup. Divide that cost by the stamps on the card to get the cost per visit.

Not quite. It is one free item after nine paid visits, so the customer gets about a tenth of their spend back only if they finish the card. Many cards are never finished, and the reward is counted at your cost, so the real cost is usually far lower than 10%.

Many shops do. A card that already shows progress feels closer to the reward, and research on the “endowed progress effect” found people were more likely to complete a card that started with stamps on it. It also costs you nothing until the card is finished.