There are two major types of headset- older, threaded headsets that have a quill that drops into the stem of the fork creating an interference connection, and newer threadless headsets that the stem is bolted and clamped on to. Flat handle bars are preferred by off road cyclists who can ride in a more upright postion whilst still having the controls at their fingertips, whereas drop handlebars offer more cycling positions and are favoured by road cyclists who typically spend more time in the saddle. The controls attached to the different styles of bar are operated and maintained in different ways.
Maintenance is the best prevention. “Prevention is the best medicine, and if you’re taking care of your equipment it’s super key. Bikes don’t just fail. If they’re in really good working condition and you clean them at night, and you’re religious about it, bikes are kind of like cars — they’ll start talking to you if something is getting worn or getting creaky or needs to be replaced.”