Tubulars deteriorate. Think of them as bananas that ripen somewhat more slowly than an actual banana. Tubulars are best used when new. At this very moment I have a couple pairs of very nice tubulars that are already getting a bit long in tooth, that I bought new--I really need to glue them up. Unlike another lister here who found gluing tubulars theraputic, I find it merely a pain in the butt.
Ideally, tubulars are stored in a controlled environment (heat and humidity especially, are death on tubulars...too dry is bad too) stretched on rims or on full wheels, in the dark.
You have to use a tubular just like you have to eat a banana..wait too long, and neither is worth much for any purpose except filling a trash can.
A properly stored and stretched tubular can last a long time, but not indefinitely. I have a few 25-year-old tubulars I ride, but they're anomalies..and the really good ones, like clement criterium setas, have latex tubes that deteriorate even faster than the sidewalls...
and I can't imagine anyone riding contis and enjoying the experience much. They're unusually bullet-proof, which is nice, but that's all you can say about them. Ride quality of the more expensive contis, to me, has been like unto what I might expect if someone made tubulars out of cement.
Charles Andrews Los Angeles
"everyone has elites; the important thing is to change them from time to time."
--Joseph Schumpeter, via Simon Johnson