Spray lubricants like WD-40 and petroleum based or flammable oils should never be used on your shredder - the wrong type of lubricant could result in fire.
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.
Most shredders can shred four or five pages at a time, but some large machines can shred up to twenty five pages at once!