Very good question Dave.
I would consider myself a runner & collector.
British outline. I did have some American & Irish but sold it off.
I have a large collection of private owner wagons, special editions, kit built etc but they're all stored away because I don't have the room to display them.
I also have lots of Wrenn, Exley & Lawrence & Goddard items, again all stored away because of a lack of room and of course lots of books ranging from late 19th century upwards.
I have a few display cabinets around the house containing mostly locomotives of which I have probably around fifty or sixty I think
I find it hard to keep track of it all. I have all my items listed in a binder & was creating a database with Microsoft Excell but got sidetracked
My layout is 23' x 9' run on NCE wireless DCC.
Haven't done anything since before Christmas as I just don't feel like it at the moment but hopefully the bug will return soon.