Choosing an Expiry Date for credit card drop down menus is a tricky business. Here’s why:

You could just pick a date in the future, say 2020, but then you might have to change the code or configuration data when credit cards start to be issued with end dates beyond 2020. This is obviously problematic because you need to know when this happens, or wait for your first customer complaint.

A better solution is to choose a year a specific number of years ahead from today’s date. All you need to know is the longest period of validity that a credit card has.

The Start Date is similarly tricky, but if you know the typical period of validity, then you can work back from today’s date to come up with a suitable year.

The trouble with this solution is that it requires thought and discussion with credit card companies, or an examination of past credit card records. This appears to be something that British Gas haven’t done on their house.co.uk website.

Instead the Expiry Date drop down has years that run up to 2999:

And they start from 1900.