Factory bought CDs-- music and movies are sealed units- they last a long time.
CD/DVD read/write- the ones that let you burn your own stuff are NOT they are plastic on one side, and a dye or a surface that is burned on the other; these are NOT a sealed, and die much faster, though not consistent from brand to brand.
I have found good information on Blueray read/write, still looking-
This is why I opened this-- I have several disks that used to have pictures that are trash.