Many people underestimate the amount of paper they think they will shred. It is better to buy a shredder that is a bit too large than to pay high maintenance fees for a shredder that is too small and, therefore, overworked.
Shredders with a safety sensor shut off automatically if hands come in to contact with the shredder's opening.
In the event of your shredder's motor overheating, turn it off for at least 15 minutes, allowing the motor to cool down before using the shredder again.