"I'd never manage without it"

Here's the fear that keeps the card in the wallet. The month doesn't work without it. The last week is the card's week. Take it away and the last week has nothing in it.

Ask what the card is smoothing. It's smoothing a month in which spending runs ahead of income by a few hundred pounds, and the card lends the difference, and the difference goes on the balance, and the balance costs interest. That's not a month that works. It's a month that's a few hundred short, with the shortfall borrowed at twenty per cent and rolled forward. The card doesn't make the month work. It hides the fact that it doesn't, and charges for the hiding.

Now imagine the month without the card, and I mean imagine it properly, because the fear is of a picture and the picture is worth looking at. The first month is genuinely tight, because the fixed amount is going to the dearest card and there's no gap to lean on. The last week is thin. You notice the thinness, which you haven't had to for years, and the noticing does something. It shows you which of the spending was the month and which was the gap. Most people who do this, in my observation, find that a fair part of what the card was smoothing was spending they'd not have done from a current account, and that the month without it is thinner but not impossible, and that by the third month it's a month.

An earlier book in this series is about saving on payday, and its arrangement is the one that replaces the card. A cushion, a few hundred pounds in a separate account, built from the fixed amount once the dearest card is clear, that does what the gap did without the interest. The cushion is what you'd never manage without. The card was standing in for it, at twenty per cent, and the standing in is why there's no cushion.

"I'd never manage without it" is true of the first month and false of the sixth, and the first month is the price of finding that out.