The amount of paper the shredder can handle at once is usually printed on the outside of the feeding mechanism. Follow the guidelines for the best performance.
A shredder makes disposal of paper documents easier - since paper shreds are more compact than crumpled paper, fewer bag changes are needed.
Many shredders can cut through staples and paper clips, however, it is advisable to remove them first since metal dulls the shredder's blades, and if the shredder needs repairing, documents in need of shredding accumulate and become a potential security risk.