Points

Loyalty points earned on purchases, redeemable against the next order.

The points screen — earn rules, redemption rules and the transaction history

Three things to set

1. How they're earned — a percentage of the order value, or a fixed number of points on specific products
2. How they're spent — how many points equal 1 in currency, and the maximum discount on a single order
3. When they expire — leave it unset for no expiry

Points can also be granted for completing actions (see store credit).

Question: Can people accumulate points to a damaging degree?

Setting a maximum discount of N% per order prevents an order being paid for entirely in points. In practice most stores set 20–30%.