>I noticed that the prices of World War 2 era slide rules have fallen to below $20 US. Fifteen to twenty years ago, they were selling for $50-$80. My guess is t

>I noticed that the prices of World War 2 era slide rules have fallen to below $20 US. Fifteen to twenty years ago, they were selling for $50-$80. My guess is that the people who used slide rules in their professions and were willing to pay over $50 to re-experience the nostalgia of playing with one again are now all dead. Not exactly the point of the article but I don't see how this follows. All this is saying is that the price of a collectible item, slide rules specifically from the WW2 era, have fallen. Collectibles change in price regularly, for plenty of reasons. On the other hand, an engineer or educator who just wants to use slide rules may not care about the specifics of when they were manufactured. The slide rule I purchased on eBay 14 years and 4 months ago as a teaching tool was $6.99 with shipping, and if anything prices appear slighlty higher now even after adjusting for inflation. I don't know what the demand is for slide rules, and I assume it isn't astonishingly high, but I disagree that inferences can be drawn from the price of items valued for their history rather than their function.