I grew up collecting British coins and most people were collecting by denomination - pennies, farthings, shillings, halfcrowns or in my case sixpences, and now even sovereigns seem to be popular! Although such collections appear to be quite common for US and world coins the same does not seem to be the case for banknotes. Now that my own accumulation of banknotes is expanding I seem to be organising them by denomination whereas most collections appear to be by catalogue number or series/printer (a typeset) rather than denomination. Design themes are understandably popular for both coins and notes. Are denomination sets really that unusual for world notes?
I can only speak to my own experience, but I would guess that the ways people collect banknotes varies as much as the way people collect coins. I've never really collected denominations, either for coins or for banknotes. I prefer to collect things that appeal to me, despite country, denomination, time period, etc. As for US denominations, collecting a full set for some of them can seem outright intimidating. Even collecting all US $1 banknotes would require a sizeable income, especially when considering the large-size bills. Even limiting that to $1 Silver Certificates in decent condition would entail paying in droves for even a few examples. I do have a "sort of unintentional" collection of small-size $1 US notes in progress, but even that includes the very expensive 1928 Legal Tender note, so I may limit that to the relatively cheaper Silver Certificates. Given all of that, I collect notes that appeal to me in the best conditions that I can reasonably afford. That approach inevitably crosses countries, denominations and time periods. Also, I typically sort my notes by country, then by denomination and then by date within denomination.
Thankyou for your reply it is really interesting to see how people collect things! Although I only have a few notes from here in the UK and a few saved from trips overseas (including the US) my main interest in world notes is Latin America. Some countries have certainly suffered from hyperinflation and this makes denomination collecting somewhat redundant, it is often accompanied by a name change just to make things even more complex. One goal is a note from each of the Mexican States (Bancos and/or Revolution) which probably means most will be 5 pesos rather than 100 or 500 pesos as they are much more available - and cheaper! I tend to favour the more classical designs, typically pre 1920's and ABNC (used some vignettes from US issues and it would be great to match these), so I can see me just buying the designs I like and in a few decades time realising I may have completed a set or two! More modern notes may be one per Pick number however completing a Latin American set like this would be a huge challenge. For now the 'not quite random accumulation' will continue
For my own country, I started out acquiring low denominations ($1 - $5) as that was all I could afford. Not long after that, I was after the signature combos, * replacements & finally scarcer signature change-overs. This evolved over the span of a decade, or so. To me, there's no point to collect a common prefix unless its UNC or a special serial number these days. When I started acquiring World currency, it was the Euro's first signature of Wim Duisenberg since I couldn't find any on my first trip to Europe (2004). I tried to pick them up on eBay but they were seldom offered & ridiculously expensive in UNC (for most countries save Germany X prefix) so I just went after a bunch of cheap dealer stock. I actually held off on collecting world for about a decade as it seemed to be a bit of an intimidating "rabbit hole" I wasn't too sure I wanted to pursue. That phase wore off quick & I decided to focus on QEII nations. My primary objective was picking up UNC since circulated notes were a dime a dozen & I wanted to start off on the right foot. I did get interested in odd denominations (2.5 G for Netherland Antilles) or $3 for Cook Islands but that was a brief phase. Lately, denomination only factors in terms of what I don't want to acquire (which is high denominations - generally 50 - 100 Dollars/Euros/Pounds). However, I have noticed that mid-denominations on island currency to be relatively scare (& often dear) so I have tried to be sure to pick some of it up!
