The other day I was out on a happy little bike ride and for the first time in my life I broke a spoke! I was just riding along and I stood up briefly to gain a little momentum on an uphill when "Boing!" and the poor spoke was no more. It's kind of amazing when you think about it that I've never broken a spoke until now...I've been riding bicycle for a long time. I did my first RAGBRAI at 12 or 13 or something (of course, back then I was probably about 100 lbs., and you don't break a lot of spokes at that size).
Fortunately, a broken spoke is not to be feared. My wheel is a bit of an old battle horse (it's the original wheel of my 1995 or 1996 TREK 5000), and the broken spoke hardly even put it out of true. I just trotted on back home, keeping the speed down on the downhills and going really wide on the turns.
In addition to the spoke, my wheel's got a little lateral play in it. What that means is that you can wiggle it side to side so that it oscillates between the brake calipers...that's got to indicate a problem.
Why is it that you can't buy this stuff and have it be good to use forever? Fortunately the front wheel on my Schwinn Circuit from 1989 still had a functional font wheel. So now I'm riding around with a 21 year old wheel with a Suntour sprint 9000 hub (I like bike gear numbered in the thousands).
It rolls...it's all good.