I have a beautiful semi-classic wheelset, Campy cassette hubs, Mavic rims, butted spokes, the stuff that begs to be seen and ridden. It is in perfect shape, with obviously very few miles ridden before I got a hold of it a few years ago. True and round.
Now, the wheelbuilder who was commissioned to do the job back in the day must have glanced at the bike it was destined to go on because he indulged in blue nipples, matched perfectly to the primary frame color.
Unfortunately colored nipples are predominantly aluminum.
One day last week I lifted the bike out of the car and sat it down a little hard. Ping! Sheared nipple. Put it on the stand, fixed it and for fun grabbed several sets of parallel spokes to test the tension. Ping! Ping! Ping! All sheared right at the shoulder where the nipple seats. No oxidation or other decay. Simply stressed from being tensioned for a handful of years. No way I was going to ride that, so on to a complete rebuild with dull, non-exciting brass
Off course this is not anything new. I have handled enough wheels to know that in one frustrating way or another alloy nipples are just not worth my time.
I will admit one, and just one, totally babied, barely ridden, race-day only aluminum nippled wheelset in the house, but it must be exceptional in every conceivable form and fashion to stay!