[user5994461]

I worked at a bank and I am reading super old commit messages all the time. In fact half of the job is reading ancient code that could use some love (#python3). I can tell you from the dates and the authors alone how hard a project is gonna be to take over and fix or rewrite.

Last sensitive code I touched is a trading platform that must be responsible for a few billions of dollars a day (could be a trillion, not sure, didn't finish adding logging). It was initially created in 2006, followed by a few commits over the couple next years, then basically untouched for the last decade or so.

Just from the first 10 commits message and the author's name. I can tell you this was hacked-in grossly over a few weeks, because everything that guy did was hacked in quickly and filled with security vulnerabilities (he worked under very limited time constraints). Yet the software does the few things it was meant to do very well, so much so that it lasted this long mostly untouched and was built upon. The history shows the critical core code has less than one patch a year, mostly fixing trivial matters like a new path or syntax change from the language. I bet the project will be moderately easy to patch and upgrade because work from that guy at that time is usually decently organized and limited in scope to the essentials.

Lesson is. If you work in a long term industry (aerospace, defense, finance, healthcare) and long term projects, it's very likely that the product will still be running a decade from now and it is expected that future developers will be reading the history of commits.