Why does nobody talk about keeping a lens log for repairs?

So for like 6 years I used to just grab whatever lens came in, fix the mechanical issue, and send it back. Never tracked anything beyond the work order. Then last month a customer brought in a 35mm that had the same aperture blade sticking problem for the 3rd time in 2 years. I had no record of what I did before, so I had to tear it apart again and guess. Took twice as long. Now I keep a small notebook, one page per lens serial number, with dates, parts swapped, and shims used. Caught a pattern on an old Pentax where the same gear kept wearing out because of a misaligned bearing, fixed that root cause instead of the symptom. Has anyone else started logging repairs this way, or am I just late to the party?