The printer is often the most expensive component in the system, but it's the easiest piece of hardware to choose. There are seven things you should know about printers:

1. The faster the printer, the more expensive it is. Speed for letter-quality printers ranges from 30 cps (characters per second) to 80 cps. Dot-matrix printers run up to 300 cps, but the quality of printing is not high enough for externa correspondence.

2. The printer is the most breakdown-prone part of the system. "It is the weakest link in the hardware system," says Michael Halvorson, chairman of Advanced Integrated Development Inc., a Minneapolis-based seller of microcomputer systems. "It has the most moving parts and it's always working hard. The faster you go, the closer you get to self-destruct."

3. A printer is useless without some kind of paper-feeding device, which almost always costs extra.The common "forms handling" alternatives are a tractor feed, which pulls up a continuous roll of fan-fold paper, or a cut-sheet feeder, which handles single sheets.

4. All good printers can use a wide range of fonts or print wheels, but don't forget to ask which ones are in stock. Frequently, only a few will be available, so make sure they're the ones you need.

5. Find out where the printer you are considering can be serviced. The Japanese own most of the U.S. printer market, so make sure you won't have to ship your printer across the Pacific for repairs.

6. Some printers make a lot of noise. Check the noise level of the one you're considering before you commit yourself to something you can't live with. An acoustical hood can cut down on the noise level, but it costs extra, of course.

7. There are often hidden surprises, so be sure to see the printer in operation, and to check out any special features you may need.