My LB rear wheel has started breaking alloy nipples (this annoying as I asked the LBS to build it with brass, guess I should have checked but not sure how you tell the difference with black nipples when the wheel is built, can you?). So the wheel needs rebuilding with brass nipps, it's 2 years old and has had a medium amount of abuse over about 1500 miles I'd have said. The spokes are Supercomps and I've heard reports of them starting to go after a couple of years, am I throwing good money after bad reusing them or should I have it rebuilt with Comps or similar?
Where are the nipples breaking? at the interface between the head and shaft by any chance? (ie: the mushroom bit on top breaking off)
If it's the above check how far the spokes actually protrude into the nipples, it's very common to see the spoke not fully past that join/intersection and thus leave the head of the nipple not properly supported/reinforced by the spoke and for the nipple to then fatigue and start breaking them after a while, and affects Alu a lot quicker than brass.
But back to your OP, personally I wouldn't bother to replace the spokes (super comps are not [i]that [/i]fragile) if they were all in good shape and undamaged, and no prior failures of the spokes, *on my own wheels*, but I might recommend differently to a customer depending on circumstances and what I know of their riding.
Not 100% sure, will take a look when I get in. Cheers for the reply