Every time I buy a new tool, I take a close up photo of it, I then have a spread sheet with it broken down into hand tools, power tools, books, PPE etc, the item then gets listed in there with price paid, description, and the filename of the photo and any serial number, if its got a serial number I also take a photo of it. This file and all images are then stored online. I also PDF a copy of each receipt where possible and tie this to it.
I then dab some Smart water on the item (got a kit and annual licence that does about 600 items). At least I know, if it all got stolen, I can hand over all he proof that I owed them and its covered I Smart water, even my screwdrivers. I actually spent two days documenting every single tool I own, every book / reference material, PPE the lot, basically anything to do with the business.
Having all copies of receipts, photos and serial numbers, and 10k of insurance does give me peace of mind. Maybe over the top, but I like it. My tools are covered anywhere, so long as they are secure, so either in ANY locked vehicle, or my house, or stored in a locked room or locked house that Is owned by a third party.