From an earlier post the question was: What is the expected lifespan of an Island.
Matt Miller mentioned that Hobie have built roto moulded Boats for 20 years. I have no reason to argue as yes these boats built by Hobie and other Manufacturers have proven their durability in hard use over the years.
In the same regard other owners have mentioned that these boats have stood the test of time much better if they are protected from the Sun's UV rays. I agree completely.
Let's also keep in mind that the Islands differ from most simple kayaks as they are also a rather complex mix of materials of a lot of plastics including rope and webbing. Here is something of the basics that were taught to me by the best in the climbing business.http://www.rei.com/expertadvice/articles/rope+care.html
If you note the article on the life of rope and webbing, they do indeed have a lifespan, as does your rigging.
If you snap your mainsheet, there are still ways to still get back home.
However, if you really want to know the component lifespan of your rig and proper maintenance, I highly suggest you read ( and study) this REI article (or technical data posted by Rope and Webbing Manufacturers.
Hint: Any machine is a series of parts to complete the intended chain. The weakest link is the one that will cause major failure if pushed to the absolute limit.