DNF'in a race or getting stranded on the trail due to equipment failure bites and gettting hurt even worse. Before you ride, you should check your bike's critical nuts/bolts to make sure everything is sufficiently tight.
This can be time consuming, so to shorten the time necessary greatly, after you've properly torqued a nut/bolt, break out your Sharpie permanent marker and mark the nut/bolt in line with a reference mark on the surface being tightened into. Then, the next time you ride, unless the mark on the nut/bolt and the surface being tightened into isn't lined up, the nut/bolt is still torqued properly.
I mark the following nuts/bolts: - handlebar clamp - brake rotors - rear sprocket - shift lever - upper/lower clamps - front axle (including pinch bolts) - rear axle & adjuster nuts
The Sharpie pen reference marks won't wash off with water, but are easily removed with carb or brake cleaners/solvents.