The UK's Royal Mail announced last week that it will be honouring Wimbledon tennis champ Andy Murray with a set of commemorative stamps.
Which set me thinking.
There's no doubt that owning commemorative stamps is great fun - particularly those extra, unscheduled issues that mark major events, whether it's the first British men's Wimbledon champion since 1936, or the birth of the future king.
But I'm concerned that many people are buying commemorative stamps in the belief that they could be worth something in a few years' time.
If that's the case - they're in for a nasty shock.
Large print runs
Because it doesn't matter whether you buy them in single packs, or as first day covers, commemorative print runs are too high for the stamps to appreciate much in value.
The Royal Mail does not generally publicise how many stamps it prints in its commemorative runs, but in most cases it is thought to be hundreds of thousands.
The 2003 England Rugby World Cup victory stamps had a run of 410,000 packs, for example.
Remember that these are stamps designed with collectors in mind. They are not going to be used, especially as the cost of the stamps is significantly more than the standard 60p for a first class stamp these days. No, they will be kept safely in a drawer or on the mantelpiece, which means the extant numbers will not diminish significantly over time.
It all ensures that the supply + demand equation that the collectibles market works on does not add up in this case.
And there's another problem.
No longer special
Up until the 1960s, commemorative issues were a huge event.
Indeed, following the first commemorative stamp, issued to mark the British Empire Exhibition in 1924, there were just a further 16 produced until 1960 - preserved for landmark events.
But then the flood gates opened.
Commemorative stamps are no longer special. You'll be lucky to get an offer of £1 for a 1969 set featuring British ships.
The Royal Mail was planning to produce 12 special issues this year alone, from Classic Locomotives of Northern Ireland to Butterflies. And that's before Andy Murray won his title.
In the States, the market is even more saturated, with the USPS set to produce five different first day covers next month.
Yes, pre-1960s Royal Mail commemoratives can achieve decent sums, with mint condition 1929 Postal Union Congress £1 examples capable of making around £1,000 - but even so, there are stronger options elsewhere.
If you're serious about building a collection worth value, I feel it is far better to concentrate on the 19th and early 20th century rarities from general usage than commemorative issues.
Their low numbers and transformation from everyday stamp to global star ensures they have a bevy of suitors.
Which is why I highly recommend a visit to our online store.
There. I've got through this week's Paul Says and only once mentioned the major baby news. But don't worry if you're a royal fan, you'll find something for you here!
Thanks for reading.