"I can always send it back"

This is the last of the three things people say at the checkout, and it may be the one that lets the most purchases through. It sounds like caution, as if you're keeping your options open.

It's also true. In the UK, if you buy online, by post or by phone, you generally have fourteen days from receiving the item to tell the seller you're cancelling, and another fourteen to send it back. You don't have to give a reason. There are exceptions, but for most ordinary goods that's the rule, and many shops offer more.

That's a good right to have. My argument is with what the thought does at ten past nine. What follows is my reasoning, not a study.

"I can always send it back" turns a decision into something that isn't a decision yet. You aren't really buying the bag, you tell yourself. You're only having a look at it, at home. That takes away the last of the pain of paying, because no money has been spent if it can all be undone. The thought works as permission to buy, however cautious it sounds.

Then look at who has to do the undoing. It isn't the brisk person who chose tan over olive. It's you on some later evening, probably a flat one, faced with finding the box, reprinting a label, taping it up and carrying it to a counter in your lunch hour. It's a chore, and there's nothing in it for you. The lift was used up days ago, and returning the thing can't bring it back. All a return offers is sixty-eight pounds you've already stopped missing.

So the bag stays. You haven't decided to keep it. You never get round to sending it back, and on day fifteen the question closes on its own.

Among the patients in Black's review, researchers recorded what happened to purchases afterwards. Some items were returned, some were sold or given away, and some were never taken out of the packaging. That's the severe end, and I'm not suggesting it describes you. But an unopened box is a clear sign that what was wanted wasn't the contents. It's worth looking on top of your own wardrobe.

Two practical things follow.

If you catch yourself thinking "I can always send it back" as you're about to pay, treat it as information. People don't say it about things they're sure of. It means you have doubts, and the time to settle them is before you order. Ask the chapter 5 question. If the answer's no, wait.

And when something you've bought on purpose turns out wrong, because it doesn't fit or it isn't what the picture showed, send it back that week. Put the box by the front door the day you decide. The right to return is worth a lot to someone who uses it promptly. It's worth very little to someone who relies on it as a reason to buy.