A supermarket loyalty card is worth it if you shop at that chain at least a couple of times a month and you actually use the discounts it unlocks. For a shop you visit twice a year it is one more piece of plastic in your wallet. The card is an exchange: the supermarket gives you lower prices, points or vouchers, and in return it learns what you buy. Knowing how that exchange works helps you decide which cards to keep.

How does a supermarket loyalty card work?

A loyalty card is a membership card with a number, usually printed as a barcode or a QR code, that the cashier scans at the till. The scan links your purchase to your account. Depending on the chain, this gives you one of three benefits: points that turn into vouchers, prices reserved for members on selected products, or personalised offers based on what you usually buy. Many chains now combine all three.

How much do loyalty points really give back?

The return is easy to calculate, and often smaller than it looks. Take a card that gives 1 point per euro spent, where 500 points become a 5 euro voucher. That is 5 euros back every 500 euros, a return of 1%. On a household shop of 400 euros a month, it adds up to about 48 euros a year. Not nothing, but less than switching a few products to a cheaper brand. Do the same sum for each of your cards: points per euro, value of the voucher, and you know what the card is worth.

Member prices are usually more valuable than points. A discount of 20% or 30% on a product you were going to buy anyway saves more in one shop than months of points.

What does the supermarket get in return?

It gets your purchase history: what you buy, how often, in which store and at what time. With it, the chain plans its stock and sends targeted offers. In the European Union this processing is covered by the GDPR, the regulation on personal data. It means the supermarket must explain in its privacy policy what it collects and why, you can ask to see the data it holds about you, and you can refuse marketing and profiling consent. Read the sign-up form carefully: the consent for personalised offers is often a separate box.

Which loyalty cards should you keep?

A simple rule works: keep the cards of the shops you visit at least once a month, and those of the shops where you make occasional but expensive purchases, such as a pharmacy or a DIY store. For everything else, the card is not worth the space. Go through your wallet once a year and remove the ones you have not used in the last six months.

Do points expire?

Often, yes. Many chains run their points in campaigns that last a year, and points not redeemed by the end are lost. Others cancel inactive accounts after a period without purchases. The rules are in the terms of each programme, usually on the chain's website or app. If you collect points for a specific reward, check the deadline when you sign up, not the week before it ends.

How do you stop forgetting the card at home?

The most common way to lose the benefit of a loyalty card is not having it with you. Changing bag, leaving the wallet in the car, a card worn so much the barcode no longer scans. The fix is to keep the card number on your phone, which you always carry. Most checkout scanners read a barcode from a phone screen without problems.

You can do it with the chain's own app, one app per supermarket, or keep them all in one place. Paniere stores your loyalty cards on your iPhone next to your shopping list: you scan each card once with the camera, give it a name and a colour, and at the till you show the code. The cards stay private to your account, even when your lists are shared with the family.

So, are loyalty cards worth it?

For the two or three supermarkets where you do most of your shopping, yes, mainly because of the member prices rather than the points. For the rest, no. Calculate the real return of the points, choose consciously what you share about your purchases, and keep the cards you use on your phone so that you never miss a discount because the plastic stayed at home.