The number of angle grinder parts you will need will be dependent on which type of grinder you purchased, what you are using it for, and how often you use it.
Professionals that use a pneumatic grinder on a daily basis have to be prepared. If their tools do not work, they cannot perform their jobs properly. For this reason, they always have o-rings and rebuilt kits for their grinders. These repairs are fairly simple because the insides of the tool come out with the removal of just a few bolts, and within 15 minutes a rebuilt grinder can be in operation again.
For the larger and more powerful angle grinders that use an internal combustion engine, the parts that are needed are greater. Just like a lawn mower or a weed eater, these need constant greasing and oil changes so the parts that need to be on hand are a grease gun and oil filters. The bearings on the angular shaft where the disc is mounted should be closely monitored and checked when not in use to prevent any problems during the operation of the grinder.
The bushings on the electric angle grinders are the most common break down component. These are simply replaced by most individuals with some mechanical aptitude. When replacing the bushings, observations for frayed and broken wires are recommended. The plug itself is a part that can show signs of wear and tear. With any electrical tool, caution should always be taken and the power source always removed when any repair is being conducted to replace any of the angle grinder parts you need to replace.