What is actually worth stockpiling at half price
"Stock up when it's half price" is the standard advice, and it is right often enough to be worth following. But applied indiscriminately it produces a cupboard full of things you bought because they were cheap, half of which you will throw out. The useful version of the advice has three conditions attached.
The three tests
A product is worth buying ahead only if all three of these are true:
- It keeps. Long enough that you will finish it comfortably before the date, in the conditions you will actually store it in.
- You use it predictably. You can say roughly how many you get through in a month without guessing. If you cannot, you are not stockpiling, you are speculating.
- The saving is worth the space. A dollar saved on something bulky and cheap is a worse trade than five dollars saved on something small and expensive.
Run any grocery category through those three and the answer usually becomes obvious.
Strong yes
Razor blades and toothbrush heads
Expensive per unit, tiny, and they never expire. Blades in particular are one of the most heavily marked-up items in a supermarket, so a half price week is a genuinely large saving. Buying a year's supply is entirely reasonable.
Laundry and dishwashing products
Powder, liquid, tablets and rinse aid all keep for years unopened and are used at a completely predictable rate. The only constraint is cupboard space. Check the wash count rather than the volume, as covered in the unit pricing guide.
Toilet paper, paper towel and tissues
No expiry, steady consumption, and the bulk packs are frequently promoted. The only reason not to buy ahead is if you genuinely have nowhere to put them.
Shampoo, body wash, deodorant, toothpaste
Sealed personal care products keep for years, and this is one of the most heavily discounted categories in both supermarkets. If you use a specific product, three to six months' worth at half price is an easy decision.
Pet food (dry and wet)
Wet food in cans and pouches keeps for a very long time and is safe to buy in quantity. Dry food is slightly different — see the caution below.
Coffee, tea and long-life drinks
Instant coffee, capsules, tea bags and soft drink all have long dates and are promoted often. Ground coffee is the exception: it stales noticeably within weeks of opening, so buy the number of packets you will get through, not the number that are cheap.
Nappies and wipes
Among the biggest recurring costs in a household with a baby, and a category where a half price week is a large single saving. Wipes keep indefinitely. Nappies do not expire — but see the warning about sizes below.
Tinned and dry pantry staples
Tomatoes, beans, chickpeas, tuna, coconut milk, pasta, rice and stock all keep for years. The individual savings are small, but they compound if these are things you cook with weekly.
Qualified yes
Dry pet food — buy the size, not the bargain
Once opened, the fats in dry food oxidise and it goes stale within a couple of months. Fussy animals notice before you do. Buy the bag size your pet finishes in six to eight weeks, even if a bigger bag is better value per kilogram.
Nappies — watch the size
Nappies do not expire, but babies outgrow a size faster than anyone expects. Buying six months of one size is a common and expensive mistake. Buy the current size and, at most, one size up.
Sunscreen, vitamins and anything with an active ingredient
These are sometimes discounted precisely because the batch is approaching its date, and the expiry on sunscreen matters — the active ingredients degrade and the stated SPF stops being reliable. Check the printed date before you buy several.
Batteries
Modern alkaline cells hold charge for years, so they are a good stockpile item, but they do carry a use-by date and a pack that has been sitting in a warehouse will hold less charge. Read the date.
Frozen food
Excellent value and no spoilage risk, limited entirely by freezer space. Be honest about how much space you actually have before you buy six tubs of ice cream.
Olive oil
Degrades with light, heat and time, and is best used within about a year of opening. Two bottles is sensible; six is not, unless you cook a great deal.
Usually no
Fresh dairy
Milk, yoghurt, cream and fresh dips are discounted because the date is close. Butter and hard cheese are the two exceptions — both freeze well, and butter in particular is unchanged by freezing.
Fresh produce
Australia throws out an enormous amount of household food, and produce is the largest part of it. Buy discounted fruit and vegetables only against a specific plan: this is going in the freezer, this is becoming soup, this is being eaten this week.
Bread and bakery
Unless you freeze it, in which case bread becomes a strong yes. A loaf frozen on the day of purchase and toasted from frozen is very close to fresh.
Chips, biscuits and confectionery
Not because they spoil, but because the saving is small in dollar terms and the presence of a large supply in the house changes how much you eat. That is a real cost, even if it does not appear on the receipt.
Anything you have never bought before
The discount is not a reason to try something. If it turns out you do not like it, you have bought four of them at a discount, which is worse than buying one at full price.
How much is the right amount?
A simple rule that works for most households: buy enough to reach the next promotion. Packaged grocery lines typically return to half price every six to ten weeks, so roughly two months' supply is the target. Buying a year of something is only justified when the item never expires, takes almost no space, and is expensive — which in practice means blades, batteries and toothbrush heads.
The honest test. Before you put a second one in the trolley, ask: "If this were not on special, would I be buying it today?" If the answer is no, the discount has changed your behaviour rather than saved you money. That is exactly what the promotion is designed to do.
The storage problem nobody mentions
Stockpiling works until you cannot see what you have. A cupboard with four half-used bottles of the same shampoo behind a wall of pasta is not a saving, it is a duplicate purchase waiting to happen. If you are going to buy ahead seriously, keep the overflow in one place, put the newest stock at the back, and check it before you write a list. That takes about a minute a fortnight and it is the difference between stockpiling and hoarding.
Related: how to plan a fortnightly shop around the specials cycle.