If, as expected, the personal writer market takes off, an abundance of manufacturers will be entering the field. Here are a few questions to ask when buying a word-processor, as suggested by the Computer and Business Equipment Manufacturers Assn. and other experts:

If you were buying a home computer, you would need to be evaluating its software. Since the software on a personal writer is built-in, there's no other solution but to try it out. Can you adjust margins? How easily? Can you easily move from bold printing to regular? Underlining? Is the editing format automatic or manual?

If the computer industry goes through another shakeout, some firms will disappear. Ask the salesman if he will guarantee service on a particular model for the next five or 10 years. If he says yes, and his store has been around for a few years itself, you should be okay. If he gets vague, forget about that model.

Examine the size of the screen. If it's important to you to be able to see great masses of text at one time, you'll be unhappy with a screen that's only 12 lines deep. And check out the resolution of the characters -- how easy are they to read? Are you going to be comfortable staring at them for hours at a time?

With all word processors, you will need to gauge the extent of their memory; with some models, there may also be a limitation on the length of each document. If you have to make a new document every three pages, that can be fine for recipes, horrible for a 20-page term paper and a nightmare for a 300-page book. And, if you're truly planning to write a very long piece of work -- a Ph.D. thesis or the Great American Novel -- investigate just how easy it is to move a scene in Chapter 2 (on one disk) into Chapter 22 (on another disk), or whether it's even possible. On the Magnavox 450, you can do this; on the 350, you can't.

If spell-checking is important, find out how many words the dictionary function includes (78,000 for the Amstrad; 50,000 for the Magnavox 450), and how easy it is to use.

Most machines are demonstrated with empty memories, which tends to give them a speedy response time. If they're riding a full disk, the entire typing process on an inferior word processor could be slowed. When this happens, the cursor may fall a sentence or two behind as you're typing, or you may try to perform a function, and then wait, and wait, and wait, before the machine does it. Ask to try out a model with a full disk.

When a document is being printed out, does the paper need to be fed in a page at a time? Even the high-quality Smith Corona 14, for instance, has no provisions for attaching any sort of feeder mechanism. If you plan on doing a lot of printing, there's a definite time factor involved here.

When you have narrowed your choice to one or two models, ask the salesman for the names of customers who've already bought them.

If all this sounds like a bit of work, it is. Customers who go in and plunk down money for the first personal writer they see may get a good deal -- or they may get burned.