the thing that destroys rollers the most would have to be lack of lubrication and the onset of rest. When your rollers get rusty there pretty much done. This is a major problem for people who live in coastal areas where the salt air will pretty much eat away at any metal moving parts of a garage door. This especially applies to homes that are located within a quarter of a mile of the ocean. Some manufacturers will offer a powder coated track system for your garage door to keep this from happening very fast. This type of track will typically last 2 to 3 times longer in coastal areas where the salt air will just eat away at the track and rollers. If you live in one of these regions then you should look into powder coated track if you are going to replace your garage door. As far as rollers go other than the natural elements there are several conditions which can put extra stress and make garage door rollers break down prematurely.

rollers have plastic wheels?

If your rollers have plastic wheels or nylon tread then they wear down on the tread of the wheel and eventually the tread wears down enough to make the diameter of the roller wheel so small that it will just pop out of the track because it is no longer wide enough to stay in the track. Rollers that use a steel wheel part of the roller do not wear down as fast as the nylon or plastic rollers and will give you a longer life and ensure that they stay in the track for the lifespan of the roller. If you have a bent hinge on your garage door and the stem of the roller is not at a perfect 90° from the track then it tends to where the roller wheel on the side of the roller that has an off angle and this will produce the same outcome. Also if your rollers are not rated for the weight of your garage door they will definitely wear out sooner than normal because I have your garage door needs a more sturdy roller to handle the weight of a custom wood garage door. Custom wood garage doors can outweigh a basic steel residential garage door by at least 3 to 4 times.

when the door is in the up position

The only time that the full weight of a garage door is resting on the rollers is when the door is in the up position. When the garage door is in the down position all the weight of the door is resting on the bottom edge of the garage door not on the rollers. So to recap the main things that I have found in my years of experience is that track and rollers not working together in sequence or in the wrong position or other damage parts that are making the rollers role in a odd position the way or of course rusts and lack of lubrication are really the only things that I have seen that will put undue stress on garage door rollers and make them fail before their lifecycle ends. You should lubricate your rollers really good and the track at least once a year if you live in a coastal region where the salt air will deteriorate any metal parts a lot faster than you should lubricate your door up to 3 to 4 times a year to stop this oxidation of the rollers and track.