Spoke lifespan

Re the earlier comment "bottom out on the thread" - that's a little misleading. A spoke nipple is usually 12mm long and the thread on a spoke is around 8 or 9mm. That means you can "bottom out" without any impact on wheel strength.

It wasn't that I was referring too. More that if you tighten a nipple as far as it will go on the spoke (bottoming out) and the spoke doesn't have enough tension then it means your spokes are too long (tangent: how much it sticks out the end of the nipple does of course matter but also its determined by rim depth - ie deep section rims will have ample room for a spoke sticking 2mm + out of the nipple before fouling the tube)