MO disks seem to be pretty durable. Never had one go bad but I don't use them a lot nowadays. I use mine to back up the hard drives on IIgs's and IIe's. Nowadays I'm in need of multi-terrabyte backup. I fondly remember buying a CD burner in the early 1990s. I could backup my whole hard drive several time over on a single CD.

There's good reason to move forward. I've recovered old files for people that had the media but no drive to read it. Sometimes I've also had to convert the files to something a modern computer could use.