Hobie breakdown?

Both fiberglass and rotomolded plastic are susceptible to UV. Fiberglass has a gelcoat coating that will oxidize and fade more than break down. The rototmolded plastic will do the same thing over time. I don't think it ever becomes a structural issue just a cosmetic one. The benefit of gelcoat is that you can buff it out. I don't think you can do much with sun faded plastic. It is generally a good idea to cover the boat with a tarp when not in use. If for no other reason than to preserve your trampoline.

The sun is king. The UV chalking is one issue. The other, which is more pronounced in a rotationally molded plastic, is that the lighter volatiles in the plastic become liberated and off gassing occurs. Modern thermo- plastics are more stable than they once were. Hardening and fatigue cracking can be an issue after long term exposure. As Dave said, a little bit of tarp work goes a long way for either materials long term survival. There are dyes that can be used to re-color certain plastic families. They work well. They are however, extremely specific upon which polymer chains they are to be used on. Several, such as poly-olefin, poly acetate and styrene butadyne can be a real PITA to do anything with. Most are hydrocarbon based and gaseous as a donkey at a Taco Bell.

Original roto-molded Windsurfers were yellow. They last 2-3 years, then the skin cracked. All replaced by Hoyle Schweitser in white. White ones began to crack after 20 years. Covering definitely necessary. Pete

Ha, i gave one of those. The white one. Weighs a ton. An original Windsurfer brand windsurfer.

Thanks. It sounds like fiberglass may still be the way to go. I use a product called ProPrep on my motorcycle plastics, but it leaves everything slick as hell. Not sure I would want it going into the water on area lakes. It removes some plastic oxidation and makes the bike look shiny and almost new.

It depends what kind of sun damage your concerned about. Sun UV seems to have a lot to do with delamination. Structurally, I have always read the roto-molded boats as nearly indestructible. The bigger issue would be whether you want the style of a boat made in a roto-molded construction.

The bigger issue would be whether you want the style of a boat made in a roto-molded construction.

Agree, don't base your boat choice on plastic vs FRP construction. Buy the boat that does what you want it to do.
I spend quite a bit of time in Barbados, the sun is stronger there. There are fleets of Hobie Waves, (same construction as a Getaway), that sit in the sun 365 1/4 days a year, with no ill effects.
They get soft on the top of the hulls, but that is due to the hulls being stood on, jumped on, sat on,(I might add that many of the users are not exactly svelte) more times in a week than your boat would see in a year.