To my knowledge it depends on how it's built.
Interesting thoughts on different boats....
The Laser - Top guys buy a new hull and try and leave it in a warm shed over summer to let the boat harden. But then (I believe because they are cheaply built) a Laser gets soft and it not usually competitive at the top levels after 3-4 seasons of hard racing.

The Etchells- Well built and although I don't know about hardening, I know old boats are very competitive, like 20+ years old.

Good read.
www.sailnet.com/forums/543126-post2.html

I don't know the answer to this specific question but offer two related issues.
An over engineered yacht like the S&S34, Brolga 33, Valiant 40 or Currawong will not suffer as much from cracking and stress fracturing than say a lightly built modern racer. I have seen minor cracking in S&S34s, all of them older and much raced hard offshore.
The relative age of the particular yacht in a class or series of yachts is important. E.g. Because MB is the youngest Swarbrick built S&S34 and has been lightly used since launching (I'm only the 2nd owner) I will have plenty of warning of major failures. As the Association has a pretty good knowledge of many of the boats I should learn of any major failures.

I am not an engineer but there is a fair bit of this on the web and in composite books.

Like most of the above posts have said - it depends. If your laminate is loaded closer to its ultimate failure load then it will take fewer fatigue cycles to propagate cracks. Polyester laminates seem more susceptible to micro-cracking. We see this as soft laminates in Lasers, Hobie 16s and Endeavours or other old yachts with single choppy laminates.

The answer is to back off the stress by making the laminate thicker, which we often don't want to do - so we accept less life and go lighter.

Fatigue is a tricky beast. The DC 3 plane has basically no fatigue limit because they over designed the plane. It is so low stressed that the number of fatigue cycles is still way into the future. Yet more modern planes, made lighter and therefore more susceptible to fatigue, have been retired.

www.boatdesign.net/threads/material-strength-and-fatigue.13174/

So a thicker, lower stressed old boat, can have a longer and stiffer life than a newer but more highly stressed laminate. Or you could just build it in wood which is really good for fatigue which is why they build trees out of it. Pair with epoxy and you have great fatigue resistance.

www.mjmyachts.com/images/stories/pdf/sp%20advantages%20of%20epoxy%20resin.pdf

Kankama said..
I am not an engineer but there is a fair bit of this on the web and in composite books.

Like most of the above posts have said - it depends. If your laminate is loaded closer to its ultimate failure load then it will take fewer fatigue cycles to propagate cracks. Polyester laminates seem more susceptible to micro-cracking. We see this as soft laminates in Lasers, Hobie 16s and Endeavours or other old yachts with single choppy laminates.

The answer is to back off the stress by making the laminate thicker, which we often don't want to do - so we accept less life and go lighter.

Fatigue is a tricky beast. The DC 3 plane has basically no fatigue limit because they over designed the plane. It is so low stressed that the number of fatigue cycles is still way into the future. Yet more modern planes, made lighter and therefore more susceptible to fatigue, have been retired.

www.boatdesign.net/threads/material-strength-and-fatigue.13174/

So a thicker, lower stressed old boat, can have a longer and stiffer life than a newer but more highly stressed laminate. Or you could just build it in wood which is really good for fatigue which is why they build trees out of it. Pair with epoxy and you have great fatigue resistance.

www.mjmyachts.com/images/stories/pdf/sp%20advantages%20of%20epoxy%20resin.pdf

Love the timber quote
Timber and plywood is a very underrated material as long as it is built right and yes lots of epoxy

hull shape is also very important in composite hulls as more modern shapes with large flat panels flex more where as more traditional shapes ie ss 34s have more compound curves which flex less causing less cracking of the resin and therefore longer lifespan this gas been changed in more modern designs by better engenereing of the layup with better cores and better resins and fibers

TopHat 25 Mk2 said..
Majority glass boats are moulded using polyester resin, its perfectly fine, later done repairs more likely to lift then the original glass, there pretty well bombarded when moulded, people bang on about osmosis, never seen in 35 years of glass boats and ive had alot.

Your a lucky fella albiet it was not a huge deal to fix even though it scared the sh.. out of me when I saw it for the first time and the burst blisters weeped

boty said..
hull shape is also very important in composite hulls as more modern shapes with large flat panels flex more where as more traditional shapes ie ss 34s have more compound curves which flex less causing less cracking of the resin and therefore longer lifespan this gas been changed in more modern designs by better engenereing of the layup with better cores and better resins and fibers

That's a critical point, Look at a UFO 34, or a Cole 32 from behind and they look like a tractor tube with a stick in the middle, Very tube like although the cole borders a bit on being a bit slabby forward of the beam due to the design of the flush deck, with more freeboard trying to maintaining head room in the cabin

I think she removed the anchor well /chain locker, glassed in a collision bulkhead and filled it with floatation.
She sealed off the lazzerets to stop water ingress from them into the main hull ( made independent storage with own pumps) and glassed over the cockpit drain though hulls.
And most probably much more on the deck.