Floppies are ridiculously unreliable. They were bad, even when they were brand new in a new drive. Failure rates of one in thirty or so wasn’t unusual. Installing large software packages was a gamble because disc 27 of 33 might have a bad sector and ruin your day.
Floppies written with one drive often wouldn’t work in another.
The drives themselves would often collect dust depending on how the fans inside the PC case were set up.
The drive head would often wear out the floppies, especially if they were used daily (e.g.: boot discs).
Keeping them in a hot car in summer could destroy them.
I learned about forward error correction (FEC) in desperation when I was in my early teens because it was the only robust way to retain data on floppies for any length of time. There were a whole bunch of compression formats that could split your data so that any n-of-m floppies could be used to recover your data in case a few failed.