Jay-
When I bought my 1987 CD-22 Cruiser used in 1998, I had issues almost immediately with the (then) new E-10 here in California. Had the carburetors rebuilt, and all fuel lines replaced, including intakes, vents, supply lines, etc. (On Edit: The old lines were not alcohol tolerant, and the ethanol alcohol loosened up all sorts of stuff in the entire fuel system.)
I was told by the dealer that the hoses ought to be replaced every 5 years due to their aging. They have the date of manufacture printed on them.
Well, it's 12 years later, and they still look good, and are still soft, supple, and not leaking or causing any problems.
If the boat were left out in the sun instead of an RV barn and, alternately, in a covered berth in freshwater, the story might be different, I suspect.
My approach is, therefore, to keep a close watch on them for signs of wear and replace as needed. The parts and labor to replace them all today is probably somewhere around $300 or so, by my "guestimate".
Joe. :teeth :thup