When I hear wildly differing stories like this I often wonder how much environmental conditions play a factor in the different experiences that people have.

Perhaps one of you is living in a much more humid and/or hot environment that causes issues with the writing process.

Tapes were constantly kept in the data center, so constant temperature and humidity 25C/50%. As I said, Tapes were changed after N uses, drives properly serviced. So if you leave them at home, in the sun in summer and in winter expose them to 10C with humidity from 10% to 90%, old drives, never clean heads… IdK That all being said, when I started working there, in my ignorance, I said “TAPES?!?! They are not reliable” due to my experience with audio tapes. But I was laughed at, and they told me about people putting 10 9 track spools in a car [0] (by the way, the same we used for billing backups!) and they went literally thousands of miles driving on partially dirt roads, in summer w/o AC, doing updates to systems, and also never ever had an issue. They were so sure they would work, that they did not take a second set, even when driving 1000 miles, and a read error would mean going back!!!

[0] https://en.wikipedia.org/wiki/9-track_tape

I suppose there could potentially be magnetic factors at play as well.