Used to, all the time. Not very much these days. One advantage is the off chance of finding something really interesting: The odd bit of paper or accessory. However, I found that good airgun related items just started to completely disappear or so expensive that it wasn't worth it. With the publication of the Blue Book of Airguns, there isn't much advantage of having unique knowledge anymore.
I ended up starting another collection hobby, Metal Squirt Guns. It's an all but completely unknown collectable -probably because I'm about the only person in the world who actively collects them- and values for most types are very inexpensive. The only really expensive metal squirt guns are the space theme types. There is a Dan Dare metal squirt gun that is extremely rare and expensive.
A few years ago, had a chance to put my collection on display in a store front (Sunlan Lighting) and took this video.
https://www.youtube.com/watch?v=dvX1ETJHqwk