Frequent discounting produces reliable short-term sales increases and a slow decline in what customers will pay. Both effects come from the same learning process.
Buyers learn the pattern quickly
A promotion that recurs on a schedule is noticed within a couple of cycles, particularly by regular customers who see it repeatedly.
Once the pattern is known, a purchase that would have happened at full price is postponed to the next promotion.
The sale still occurs, at a lower margin, and the promotional uplift records it as incremental volume.
Categories bought on a routine, such as household staples, learn fastest of all, because the customer has many opportunities to observe the cycle within a year.
Reference price moves toward the discount
People judge value against what they believe the item costs, and that belief is formed by the prices they have actually encountered.
When the discounted figure appears often enough, it becomes the reference, and the list price reads as an inflated starting point.
The brand then has to discount to achieve normal sales, which is a permanent margin reduction rather than a temporary one.
Measurement makes it look successful
Promotional periods show higher volume than the weeks around them, which is the comparison most reporting makes.
That comparison cannot distinguish new demand from demand that was postponed into the period and would otherwise have arrived earlier.
The honest test compares a full cycle including the periods before and after, against a matched period without promotion, which is rarely run.
Who the discount actually reaches
Blanket promotions are received by everyone, including customers who were about to buy at full price.
The margin given to those buyers is a straight cost with no behavioural change attached, and they are usually the most valuable segment.
Targeted offers restricted to lapsed or price-sensitive customers avoid that transfer, at the cost of complexity and the risk of the offer leaking.
How the pattern is broken
Unpredictability is the practical lever. Promotions that vary in timing, depth and mechanism are harder to wait for than a fixed calendar.
Changing the form of the incentive helps too, since added value that does not touch the headline price leaves the reference intact.
Withdrawal is slow in either case, because the expectation was built by repetition and only decays the same way.