Optical media in general has already existed for more than 20 years, something people seem to forget. If stored properly and taken care of, optical discs will last decades. To be completely safe, and to take full advantage of the ability to make lossless copies, it is suggested you make new ones every 10 years or so, maybe more often if you're paranoid.
While some people can claim media dies in months, their results are almost always (99% or more of the time) actually related to other issues or lack of initial proper testing altogether ("proper" meaning more than just PI/PIE stuff, which has limited value). No disc should ever die in under 10-20 years unless it was either mistreated (not taken care of, not stored correctly) or misproduced (meaning it was bad before it was burned, be it dyes or glues).
Nobody can give an exact date, and nobody ever can. It will always be a range, just like anything else in the world.
Buy good discs (TY, MXL, MCC, etc) and then store then in cases at room temperature and you won't have troubles.