While most food processors run off electricity, some smaller choppers operate manually. For large, electric appliances, look for a model with sufficient power to quickly chop the quantity of food it’s holding, efficiently and without burning out the motor after just a few uses. Experts suggest avoiding food processors with less than 300 watts of power, and as devices increase in size (more on this factor, soon), the size and strength of the motor should also increase. Once you get up to food processors that hold nine or more cups, you’ll need at least a 600-watt motor to ensure your processor operates efficiently and lasts a long time. If you want a manual chopper, be sure to get a small one, as a large manual chopper will often require more effort than it’s worth.