When I purchased my wife's vehicle a few years ago, the Honda dealership gave us a complementary CARFAX account. Initially it only had her vehicle in there with all its maintenance so it was just there. Nice to have but I didn't really do anything with it. Then I got curious about adding my VW into the virtual garage and it took that with no problem, no extra fees. All the VW's recorded service history automatically filled in, which was nice.
Jump to last year when I got my Jeep. It was a surprise that the PO had kept decent records in the owner's manual; oil changes, oil types, and whatnot. I wanted to keep up with that practice so I looked for a book or something similar to use, then it hit me. Why not just use CARFAX since I knew the Jeep's history was there while looking online at the thing before I bought it? I added it to the virtual garage and now I add everything I do as "DIY Service" when I complete something.
Most shops add their work to CARFAX too. When I had a new spare mounted to match the other 4 tires, PepBoys put it in as "Service Completed" but I went on and added "New Spare Tire Mounted and Balanced". Adding that detail to records is easy, most everything auto-prompts once you start typing a few characters.
I'm not planning on ever selling it, but if I had to, at least someone else would know what's been done when they look up its history.