Take a gander at your shelves and folders and give an estimate (or calculation) of how many of your RPG products (print and PDF) have seen use in actual play.  You get to decide what counts as seeing actual play, but I hope we can at least all use the minimum standard that you could actually identify what elements were used rather than a general vague notion of increasing setting knowledge or general inspiration.  If you really want to count that as use in actual play you can, of course.

For me, it's definitely less than 10%.  I tend to get a new thing every month (mostly PDFs these days) or so and have been playing since Holmes D&D and have branched into a huge variety of games.  While I have sold some stuff, I think I'm still under 10%. Maybe even 5% if I count all books I ever owned.

EDIT:  You can also share how often you play if you want to give some context.  I run a weekly game, and a monthly game and play in another weekly game and another monthly game.

I would say 80% on a book by book basis, though a good chunk of that would be for one or two sessions or for supplements that don't see regular use.

40% easy. And it was higher before I purged the shelves.

Maybe 10% with a very generous definition of actual use that includes using one thing out of a hardback that is hundreds of pages long or running a game one time.  5% is probably a more realistic number though.

Easily under half of my in-print because there's so much to explore within each "imagination seed packet" (book). There's lots of setting expansion material I can't reach because there's not enough shared time for my friends and I in our adulthood.

If we're also including .pdfs, then we're talking less that a quarter, maybe even under 10%. That is because I got all ambitious and crazy with free products and the quest for that perfect new system. In the end I found I was searching and learning systems more than playing, which was detracting from shared playtime with friends.

In the end the novelty of new systems with friends was less fun than enjoying new campaigns with old systems. System familiarity made the mechanics fade away more and the fun stand out in relief. Yeah, I crossed the old, fuddy-duddy line now...

Less than 0.1%. But I'm a big collector.

5%-10%

Hmm.... Probably about 5% of the core rule books I own have been actually played. (Not counting the collection of 1000+ free RPGs I've collected off the internet over the years.)

Probably around 50% of my total collection has seen use in actual play.

If we're talking print items, hrm.  A good bit higher than it used to be, since I sold off most of my collection a couple years ago.  Like many another gamer, I spent my first several years grabbing damn near everything that caught my eye, so I had 1st ed copies of Recon, Runequest, Shadowrun, Ysgarth, Lee Gold's Japanese conversion of C&S, and all manner of adventures I'd never touched, mostly for Champions.

Now?  Hrm.  I've got originals of the Judges' Guild Tarantis and Viridistan "city-states," some author's/contributor's copies of sourcebooks in systems or milieus I never actually GMed (GURPS IST, Battletech, MERP, DC Heroes, the like).  By page count, I probably use or have used about 60-70% of what I have left.

I have the habit of buying new games I see that are not like any game I have or that cover genres or play styles that aren't covered by games I already own just to see how they handle the material.  I am also a sucker for certain genres like anime based games or horror themed games.  I am also a sucker for a sale.  I rebought a bunch of stuff for Mekton even though I haven't run or played that game in 15-20 years because it's nostalgic for me, anime themed and was heavily discounted.

Currently, I'd say about 90% conservatively.

I have strict rules for my game shelves.

Every year, I review the collection. Was something used this year? Great, it goes to Section One. "Used" means I played it or used it for prep.

If it wasn't used this year, it goes in Section Two. If something stays in Section Two for 3 years, it gets sold on eBay UNLESS it is something so rare and wonderful that I fear would be hell to replace (like my OA 1e 1st printing).

This works for me because if something stay in Section Two for 3 years, its lost my interest. When I review Section Two each year, I put stuff aside to run at cons. If the con game doesn't happen, I usually recognize that game has lost my interest.

I don't cull PDFs, just dead tree. I've got 100s of free PDFs I haven't read.

Quote from: yosemitemike;874744I rebought a bunch of stuff for Mekton even though I haven't run or played that game in 15-20 years because it's nostalgic for me, anime themed and was heavily discounted.

Mekton is just plain good.  I haven't played it as an RPG in quite some time, but I do still use it for miniature wargaming with whatever sci-fi miniatures I want every 4 or 5 months or so.

The results have been very interesting so far.

Quote from: NathanIW;874753Mekton is just plain good.  I haven't played it as an RPG in quite some time, but I do still use it for miniature wargaming with whatever sci-fi miniatures I want every 4 or 5 months or so.

The results have been very interesting so far.

I wouldn't have bought it otherwise but there is next to no chance that I will ever use those books in a game.  I basically just bought them to have them.

At one point or another I have given all my games a whirl. Even 4e D&D Gamma World.