I know some stuff does have weight limits, I try to err on the side of caution. I use 36 hole wheels, a steel frame, an alloy steer tube, alloy bars, etc.
I was using the old Time pedals, the black ones, and when the first one broke, I crashed at low speed. We figured it was a fluke, so Time gave me a new set. When the second one broke, I didn't crash, but the Time rep upgraded me to the white expensive ones no charge. When one of those broke, I crashed again and the Time rep bought me a pair of Looks.
I have also broken 3 steel frames, several seatposts, seats, a stem, and too many wheels and spokes to remember. The mountain bike has seen a broken fork, 2 blown shocks, and several wheels.