Perishables reprice by the hour and durables by the quarter

Everything here earned its place by changing an outcome. Nothing about repricing speed is included to round the number up.

Decay sets the clock

A product that becomes worthless tomorrow has to be repriced today, while one that will be identical in six months faces no such pressure. That is why fresh food moves through reductions within a single trading day and a hand tool can hold one price for years.

Everything in between sits on a spectrum defined by how quickly the goods lose value rather than by how popular they are. The rhythm is a property of the category, and it is stable enough to plan around once you have noticed it. Asking how fast this thing goes off, dates or goes out of style tells you how fast its price can move.

The daily clock in fresh food

Reductions on short-life food typically follow internal rules tied to remaining shelf life and to the trading day, applied by staff at set points. The timing differs by shop and by country, and staff will usually tell you when the rounds happen if you ask politely.

Per unit, the deepest reductions come latest, by which point selection is whatever nobody chose earlier in the day. Buying this way genuinely reduces cost and waste, but it only works if you can use or freeze what you find. A reduced item you throw away has cost you its full price and then some.

The quarterly rhythm in durables

Durable goods lose value slowly, so their prices respond to stock levels, competitor moves and model cycles rather than to a clock. Movement therefore clusters around events, and between those events prices can sit unchanged for long stretches.

At the till, that makes alerts far more useful than checking, because there is nothing to see for weeks and then something to see for a day. It also means a durable at an unusually low price is usually there for a structural reason worth identifying. Slow categories reward patience differently from fast ones: you wait for an event rather than for a time of day.

The awkward middle

Goods with a long but finite life, such as packaged food, toiletries and household chemicals, reprice on promotional cycles rather than on decay. Their dates are distant enough that shops can hold them, so reductions reflect buying deals and shelf competition instead.

This is the part of a shop where multibuy offers and rotating promotions do most of their work. Because the goods keep, buying ahead when the price is low is genuinely effective in this middle band. It is also where storage space becomes the limiting factor rather than money.

Matching your habits to the rhythm

For fast categories, the effective tactic is being in the shop at the right time and being flexible about what you take. For slow categories, the effective tactic is knowing the event calendar and having an alert set well ahead of it. For the middle, the effective tactic is a shallow stockpile of things you certainly will use.

Applying the wrong tactic to the wrong rhythm produces effort without saving, which is how people conclude none of this works. Sorting your regular purchases into the three rhythms takes one afternoon and then keeps working.

Retailers vary discounting by region and by account, so the price on your screen may differ from any quoted here.

Where the rhythm breaks

Supply disruption flattens everything, since a shortage removes the pressure to reduce anything at all. A shop changing format or ownership often changes its reduction rules, and old habits stop paying without warning. Online grocery removes the end-of-day mechanism entirely, replacing it with substitution and date guarantees that work differently.

At the till, none of these are predictable, so treat any rhythm as an observation to re-check rather than a rule to rely on. The underlying principle survives even when the specific pattern does not: value decay sets the speed.

Everything above, in order of what to do first

1. Decay sets the clock. A product that becomes worthless tomorrow has to be repriced today, while one that will be identical in six months faces no such pressure.
2. The daily clock in fresh food. Reductions on short-life food typically follow internal rules tied to remaining shelf life and to the trading day, applied by staff at set points.
3. The quarterly rhythm in durables. Durable goods lose value slowly, so their prices respond to stock levels, competitor moves and model cycles rather than to a clock.
4. The awkward middle. Goods with a long but finite life, such as packaged food, toiletries and household chemicals, reprice on promotional cycles rather than on decay.
5. Matching your habits to the rhythm. For fast categories, the effective tactic is being in the shop at the right time and being flexible about what you take.
6. Where the rhythm breaks. Supply disruption flattens everything, since a shortage removes the pressure to reduce anything at all.

The takeaway

Ask how fast the thing loses value, because that sets how fast its price is allowed to move.

A discount is a claim about a price you were never asked to pay.