Something never felt right with how Udemy promoted courses. I used to have a top selling course there, selling thousands of copies a month and now it gets basically no sales but it's still one of the highest rated courses in that niche on their platform. It's just no longer ranked or promoted by Udemy, for years.
I have no evidence of this but my personal opinion is their ranking is probably not fully automated and they have special offers and deals with certain instructors and if you're not a part of this club, oh well.
Again, it's all speculation but I can only go by what my numbers are. They were small scale life changing and now nothing but the quality of the courses I produced didn't change. It doesn't make sense. Of course it could be one big coincidence too, but this has been tracked and analyzed over years.
My oldest disc is some bright blue Verbatim disk my childhood friend made for me so I could play our favorite game at home pre-2000. I have a bit-perfect copy, but the actual disc still reads fine in 2025 when I last tested it.
My team used to maintain go-kits for continuity of operations for a government org. We ran into a few scenarios where the dye on optical media would just go, and another where replacement foam for the pelican cases off gassed and reacted with the media!
I have no doubts (hence my anecdata statement) that there could be bad DVDs in there, or that maybe over a longer time horizon that the media would be cooked.
Not old enough to have this kind of knowledge or confidence. I wonder if instead one day I'll be helping some future generation read old floppies, CDs, and IDE/ATA disks *slaps top of AT tower*.
After 10 years, which was longer than the assumed shelf life of writable/rewritable DVDs at the time, I never found a single corrupt file on the disks. They were stored in ideal conditions though, in a case, in a closed climate controlled shelf, and rarely if ever removed or used.
Also, just because I think it's funny, the archive was over 4000 DVDs. (We had a redundant copies of the data compressed and uncompressed, I think it was like 3000 uncompressed 1k compressed) there was also an offsite redundant copy we put on portable IDE (and eventually SATA) drives.