Rebates, vouchers, points and credits are all promised value that may never be collected. The uncollected share is a planned input to the economics, not an accident.

The gap between issued and redeemed

Every promotion that requires a later action produces a difference between what was offered and what is eventually claimed.

That difference arises from forgetting, from missed deadlines, from lost documentation, and from the value being too small to justify the effort of claiming.

Because the pattern is stable across campaigns, it can be estimated in advance and built into the cost of the offer before it launches.

Deferred value costs less than immediate value

An offer paid at the till costs its full face value on every transaction. The same offer paid later costs only what is actually collected.

This allows a larger headline figure for the same budget, which is why deferred mechanisms consistently advertise more generous amounts than immediate ones.

The size of the advertised offer and the difficulty of claiming it therefore tend to move together, since the second funds the first.

Friction is a variable that can be tuned

Requirements to register, submit proof, wait a period or claim within a window all reduce the proportion collected, and each can be adjusted.

Sellers face a limit, because excessive difficulty produces complaints, regulatory attention and customers who do not return.

The mechanism works best where the process is genuinely straightforward but requires the customer to remember to act, since forgetting produces the effect without the resentment.

Accounting rules constrain the practice

Unredeemed value represents an obligation, and accounting standards require an estimate of it to be carried until it expires or is used.

Recognising the benefit early requires evidence for the estimate, which means the redemption pattern must be documented rather than assumed.

Several jurisdictions further restrict expiry on stored value, which limits how quickly an unclaimed balance can be treated as the seller's own money.

Evaluating a deferred offer

The useful question is what the offer is worth after allowing for the probability of actually completing the claim, including every step required.

An immediate discount of a smaller amount frequently beats a larger deferred one on that basis, particularly where several conditions must be satisfied.

The comparison also has to include the effort itself, since the time spent claiming is a real cost that the mechanism is specifically designed to impose.