I was once on a team piloting a new inventory planning model in Excel, testing it out at a handful of distinctively different manufacturing sites to stress test it before paying SAP's ransom to bake it into the official system.

When I started, I was backfilling someone who created the Excel model and was responsible for batch exporting data from SAP, crunching the numbers in Excel, and sending that out to the sites every morning. My onboarding consisted of being given his laptop and his login credentials[1], and being met with a desktop full of dozens nested folders of Excel sheets in that exact version control format. I still have nightmares of that week.

[1] My manager had successfully kept IT from being able to get the laptop for re-imaging. But my senior VP located on a different continent had to get involved to get IT to reset the guy's password for us.