How do I remember all these pin numbers?

Never let it be said that the British banking system lacks compassion. Tomorrow, Valentine's Day, is also being advertised as "chip and pin day". But it's only from the day after that we'll be required to use pin numbers for all face-to-face card purchases in the UK - thus sparing chivalrous Valentine dinner-buyers embarrassment. "We did give some thought to this," says Sandra Quinn of Apacs, the payment processing association. "We didn't want anyone's marriage proposal to be ruined by chip and pin."

From Wednesday, though, things get tricky. According to research reported yesterday, half of us have trouble recalling our pins; a quarter have eight different numbers to memorise. More than half those surveyed had made all their pins the same, which banks advise against. Things are no better with computer security: surveys reveal just how many of us, ingeniously, use the word "password" as our password. ("Secret" is also popular.) Our brains are out of step with technology. What can we do?

For passwords, the strategy is simple: no word is safe, because a hacker can plough through the dictionary. The solution is multiple words and bits of words, interrupted by numbers. But four-digit numbers are problematic. The pin system is a trade-off between making security good enough and transactions fast enough. To weight it in your favour, you need numbers that are meaningful to you, but that no thief might imagine were meaningful.

This means (despite some recommendations) that dates of birth and birthdays are out, especially your own, as it might be visible elsewhere in your stolen wallet, and any whole year, since it will inevitably begin with 19 or 20. The end (but not the beginning) of a phone number (but not your own) may be a little safer. Any combinations of numbers (your parents' house number, followed by your in-laws') will be safer still.

Some suggest a rule that relates every pin to its card - eg, using the third, sixth, ninth and 12th digit of each card's number as its pin. But your rule needs to be fairly complex. And not one you just read about in a national newspaper.