Disc life is 25 years before it starts eroding. If you want to see what the process looks like speeded up, look at VHS tapes.
There's no firm, predictable number of years as you're suggesting. I have nearly 40 TG-CD/PCE-CD games that have survived 25 years and not a single one has signs of becoming degraded. The quality of manufacturing and the way the disc has been handled are two factors that you have to consider.
scoobs22, anecdotal evidence means nothing you know? 25 years passing doesn't mean the suddenly break, it means the risk starts to climb from this point onwards.
Yes, I understand that. I also understand that when media manufacturers put a lifespan on their products, they don't really know if it's accurate, and they err on the side of caution to cover themselves. When it comes to how discs are holding up, I guess my collection is all I care about, and my collection is fine.