I keep everything in a storage box in the rafters as I like to have the references and everything in one place though I do have a Marlin 983S that the FFL put the wrong serial number on the paperwork. I just wrote the right one above it, stuck it in a labeled envelope with the rest of the paperwork that came with it (manual, receipt, etc.) and into the storage box with the rest of them. I pretty much keep everything that comes with them except the cable locks (I prefer my own) and cardboard. I do keep any hard cases.
I also keep an active computer file (two actually) on all of them. Each has it's own page(s) with all the information in the header (the when & where I bought it, serial number, model number, caliber(s), added accessories, deleted accessories, image and so on.) and large 3 ring binders for hardcopies. The first one has a round count, brand and lot #, and a rating of 1-5 by performance. The second one is a dupe of the first except it's my reloading information, recipes, and performance for each individual one. I also store any worthwhile receipts for each behind their page in order.
It only takes about 5 minutes to update them and print a new page(s) after a range session and maybe 10 minutes to build a new one. I know it sounds retentive but it's helpful, at least in my case. Without getting into numbers of, I do maintain 27 different calibers by way of stocking.
As for the state and their new game, they can go to hell. They want to change the rules and make everyone a felon, I hope they have the prisons and a new tax base to support them. Bunch of maggots.