I went 100% digital a few years ago. Got a Fujitsu "scansnap" scanner and went crazy turning everything into 600 dpi, color, searchable PDFs. Then I backed that up, then backed up the backup, then backed it up a third time. Then I shredded all the paper that wasn't a "keepsake" with sentimental value. Every few weeks I scan any new items like receipts, tax documents, etc. and that would include all gun receipts.
One hard drive sits at home backing up my PC on a regular basis. A second one is in a fireproof safe at work which I swap with the home one every 3-4 months, and a third is a relative's house several hundred miles away which I swap every 9-12 months. Hard drives fail, but I figure that's pretty safe.
My goal in life it to keep things as simple and uncluttered as possible, and I find that digitizing everything to a couple hard drives is way better than files of paper.