Despite the prevalence of electronic devices, a great deal of current technology relies on more traditional machinery to get the job done. For example, gears still play a large role in many important machines, from wind farms to heart pumps. To save cost and weight, many gears are made of plastic.

Unlike metal gears, plastic gears are completely immune to corrosion.

Gears made of plastic tend to be lighter in weight than similar gears made out of metal.

Plastic gears are, in general, less expensive to produce than those made of metal.

Plastic gears can warp under strain. This can be a problem if the plastic becomes hot.

Plastic gears can have their teeth worn down from repeated use. While this is true of any gear, plastic as a material isn't as durable as metals, though manufacturers can add coatings for the teeth.