It depends on how much sun exposure its had. Inflatables are either made of PVC or Hypalon. The most common, by far, being PVC. PVC WILL breakdown in UV over time. The evidence is delamination. The first thing to go are the pieces which are glued on (oar locks, life line attachments, tow eyes). Then things like the floor and seams start to go.
If the PVC is heavily discolored it has had a lot of UV exposure. This is why the manufacturers only warranty them for 5 years. I've gotten 15 years out of one with regular use. I deflate it, roll it up and store it in the cabin during the week and only use it on the weekends. Those that sit in davits all season, or the deck of the boat tend to not fair as well.