When can I reuse a calendar?

Peter Beadle has spotted a website that shows when a calendar from an earlier year can be used again - you just need to change the year! He says "here is a really useful website if you want to recycle your unused Classic Car Calendar or that unused W.H. Smiths Diary you were given 10 years ago. Just change the year date for other interesting uses". Website

Posted: 201216
What do you mean I can re-use calendars - this one ended on 31st December 2005?
As it turns out, the annual calendar cycle is pretty predictable and the days of the week repeat every few years. This means that all of the days of the week match up, including possible leap days. Many if not most holidays will match up, too.

For example your 2020 calendar is reusable in: 2048, 2076, and 2116.
In 2021, you can reuse calendars from these years: 2010, 1999, 1993, 1982, 1971, 1965, 1954, 1943, 1937, and 1926.

But often a calendar was not used because it is either not attractive or not the right size - or in the case of a Pirwelli calendar it was a collector's item from another era!