I think I actually broke it on a ride last week. I remember stopping quickly before crossing South Road, only to have the car stop and wave me across. There's a little bit of an uphill on the path there, so it's always hard to get going again, and somehow I managed to be in gear a couple of cogs too high, so I wasn't moving at all. So I pressed down extra hard, and heard a "poink" as I started moving. Nothing seemed awry, so I didn't stop to check any further. It was similar enough to the click my left pedal occasionally makes when it's stressed that I just assumed that was it.
Tonight, I was about two miles onto my ride when I noticed a rubbing noise. Looked down between my legs at the rear wheel and finally noticed how out of true one section of it was. I tried nursing it back, but it just got worse, so I walked it the rest of the way. I've put about fifty miles on the bike since I heard the "poink," so it'd already had plenty of time and stress to knock it way out of shape. Bother.
I'll take it to the bike shop, but I fear the worst. If a wheel gets that far out of true, it usually has to be replaced. I know this because I'm on my third rear wheel on the Univega.