Do I have to put this in my accounts?

It depends on your jurisdiction, the size of the programme and whether customers paid for the value. Prepaid value is generally treated more strictly than earned rewards. Ask your accountant.

Does expiry solve it?

It bounds it. It also has consumer-law implications for anything customers paid for, and aggressive expiry damages trust. Bound it thoughtfully rather than reflexively.

Loyalty liability: what you actually owe

Every unredeemed stamp and unused voucher is a promise you have not kept yet. Multiply outstanding rewards-in-waiting by what each costs you, not by menu price. The number is usually smaller than owners fear and larger than they had considered, because most have never calculated it.

Most owners have never calculated this number, which is the main reason it feels alarming.

What counts

Every part-filled card represents a fraction of a reward you will eventually hand over. Every unredeemed voucher is a whole one.

Sizing it

Count the rewards currently earned but not yet taken, plus outstanding vouchers. Multiply by your cost, not the menu price.

For most small hospitality programmes the honest number is a few hundred dollars of input cost. That is worth knowing precisely rather than worrying about vaguely.

Prepaid is different

Value a customer paid for is a stronger obligation than value they earned, both commercially and legally. Keep the two separate in your head and in your records.

The paper problem

With punch cards this number is unknowable. Cards in circulation are invisible, so you carry a real obligation you cannot size. That is the strongest practical argument for a digital programme, ahead of any marketing benefit.

Breakage is not a plan

Some of it will never be claimed, which reduces the eventual cost. Do not build on it. High breakage means customers gave up, and a programme people abandon has already stopped doing the job you are paying for.

Before a big promotion

Work out what it would add to the outstanding total if everybody redeemed. That one calculation catches most of the promotions that would have cost more than they earned.