[ghaff]

There was definitely a period, at least with 5.25" disks, when name brand disks like Verbatim definitely tended to be more reliable than cheap disks bought in bulk. The latter weren't that bad (usually) and it often still made sense to use them so long as you were extra-careful with backups.

In general, failed floppies weren't a weekly occurrence or anything like that. But a floppy that couldn't be read or at least developed bad sectors was not rare either.