1. Users - If you are the only user and you will be shredding just a few pages at home everyday, the smallest personal shredder will suffice. Large busy offices will need an office or commercial/departmental shredder that can handle constant use and larger capacities of shredding.

2. Security - You can choose between strip and cross cut shredders that will reduce material to pieces of varying sizes. Cross cut shredders provide more security as they reduce paper to small confetti like squares whereas a strip cut shredder will shred a sheet of paper vertically into strips. High security shredders are available that meet Department of Defense, FACTA, HIPAA, and other restrictions for industries regulated by the government.6

3. Sheet capacity - If you think that number of users may not be a good way to find a shredder (because users will be shredding either abnormally large or small amounts), then sheets per day or sheets per pass may be better ways of evaluating a potential shredder.

Sheets per pass is the number of sheets a shredder will accept at one time. They range from about 5 for a personal shredder to 500 or more with large industrial shredders. Hospitals and law or other offices needing to shred entire files or stacks of paper at one time will want to look at a larger commercial or industrial shredder.

Sheets per day is the number of sheets a shredder will accept in a day. This is a good measure if you plan to use the shredder continually all day or at intervals for capacities that max out the shredder's sheets per pass. Large industrial shredders will provide a value in tons per day.

4. Materials being shredded - There are some regular paper shredders for home and office use available that will handle paper with staples, paper clips, as well as CDs and credit cards. Some models will have a separate slot to insert CDs and credit cards. Industrial paper shredders are available for a business to shred cardboard for packaging, as well as metals, plastics, fabrics, and other materials.

5. Features - Optional features/accessories include automatic oilers, conveyors, balers, CD slots (see "Materials being shredded"), automatic safety features, and more.

Automatic oilers are add-on containers that store and dispense oil as the shredder is used. Shredders should be oiled regularly for optimal performance, and automatic oilers will do this without an operator remembering to oil at certain intervals. Auto oilers are usually only used on industrial shredders.

A baler is a machine that condenses shredded waste into compact cubes, or bales. The bales can be disposed of much more easily than large, industrial volumes of shredded material that simply fall into a collection bin.

Safety/efficiency features include auto start/stop so an operator can simply feed paper into the opening without turning the shredder on or off. Reverse mode easily clears paper jams, and various other indicating lights to tell when there is something that needs attention.

Conveyors belts are optional on some industrial shredders to automatically feed paper into the opening as the shredder is working. This allows a user to put down much more paper than the shredder shreds in one pass and leave it to the shredder to feed itself the paper as it can handle it.

6. Space - look at the dimensions of the shredder to make sure it will fit into the space where you want to store it. People who buy shredders are sometimes surprised that they don't fit under their desks or in the corner of the office where they wanted.