I don't collect stuff in a methodical 'must own every issue/version of x, y and z' sort of way. It starts out with me buying something and after a few years I realise I've got a load of items in a certain field and it becomes a collection. I needed to make more space earlier this year so a lot of the computer graveyard got junked or given away. I know what you mean EmGee DK, some of that stuff cost a packet back in the day. Anyway here are three things which I think count as collections:
1. Records. I suppose most of us own a music collection, but I love the physicality of mine because so much of it is on vinyl from when I used to DJ. It weighs a ton but I'd never sell it, some records would be hard to replace. I'm slowing making high quality digital copies.
2.
Swords. A bit of an odd one for me because I'm a lefty-liberal-pacifist.

I used to do quite a lot of theatre so I first encountered them as stage props. A friend's father use to forge swords for film and TV (he made the Braveheart sword) and that made me interested in their production. I bought a (fake) samurai sword in France and then a sabre at a theatrical suppliers in Camden. They were kind of the equivalent of a £100
Halfords mountain bike.

Later I started buying better quality (the
bottom two in the photo are real hand forged swords). My interest is in the metallurgy and mythology rather than their use. I think they look beautiful but I've put them away now for obvious reasons of safety (I don't trust visitors not to do foolish things like testing how sharp they are).
3. Herbs and spices. I think my two shelves of herbs and spices now count as a collection.

I'm a keen cook and a good range of flavours is essential. Ok it isn't like stamp collecting, but I use them every day.