A battle-scarred but resourceful old politician gave me a salient piece of advice when I got into this column-writing business: "Keep your words soft and palatable," the old pol said, "because sooner or later, you'll have to eat them."

It was excellent advice, and, naturally, I ignored it. Veteran readers will remember the harsh and bitter words I used in this space to describe those software programs that balance a checkbook. What a waste of time and money, I used to write. You could do it faster with a pencil and a calculator, I insisted. If balancing a checkbook is your only reason for buying a computer, I argued, you don't need a computer. Gentle reader, pass the salt. Today I eat those words.

I still don't think that balancing a checkbook is reason in itself to buy a computer. But then, no practical application is. The real reason to acquire your own computer is to acquire the sense of power and the fun that comes with using this marvelous tool.

But there are, in fact, many practical uses of computer power, and I've recently discovered that keeping track of a personal or business checking account is one of them.

I've had all my far-flung checking accounts on the computer for a couple of months. For the first time in history, I know precisely where the money's going and how much I have left -- even between monthly statements from the bank. I programmed the machine to check the bank's interest computation, but that feature hasn't worked yet because nobody at my bank has been able to explain exactly how the interest is calculated. (If you want to see a branch manager squirm, go in and ask your bank to explain its interest-computing formula.)

If you're interested in putting the computer in charge of your checkbook, do not, repeat, do not, go out and buy one of those programs specifically designed to balance a checkbook. If your computer dealer wants to throw the program in free when you buy the machine, that's fine. Otherwise, those programs aren't worth the money because you can do the same job many other ways.

For one thing, you can write a program of your own in BASIC, Pascal, or any other language your computer knows. We put together a quick-and-dirty version in about 40 lines of BASIC.

Even better, you can make a checkbook checker on many standard applications programs. If you have a word processor, database manager, or spreadsheet (and every computer owner should have at least one of those three), you can turn it into checkbook checker.

If your word processing software has a "columnizing" feature and simple math functions -- fairly standard equipment on programs in the $200 range or higher -- you can set up a file called "checks.doc". You just type in number, explanation and amount for each check or deposit and the program will tabulate a running balance automatically.

Somewhat more powerful is a checkbook system made from your database management program. These programs were designed, after all, to keep track of and organize large quantities of records -- things like employe histories or purchase orders. A check is a very neat little record of a particular transaction.

In the checkbook mode, you just treat each check as an individual record. You enter all the pertinent information about each check; then the program takes over. It can give you a listing of account activity with an up-to-the-minute balance, but that's just the beginning. It will list -- in order of date, amount, payee, or whatever -- any series of checks in any category. You want to know all the checks you wrote for medical bills between January and December of 1984 that weren't reimbursed by insurance? It's a snap.

For some reason, not many data management packages emphasize this ability. One big exception is IBM, which offers a neat little package ("IBM Executive Solutions") to make a checkbook checker out of the IBM Assistant or PFS: File/Report database programs. It works perfectly.

The most powerful way to track your checks, though, is on a spreadsheet. It is an extremely simple process to design a spreadsheet grid that lists check number, date, payee, explanation, tax-deductible status, and amount for every check -- and then, in the last column, keeps a running tally of the account balance. If your spreadsheet has a date function, you can make it add in automatically any regular deposits, or subtract regular checks and charges. It can compute the interest (if your branch manager knows the formula).

In essence, this program gives you the equivalent of a monthly account statement -- but with much more information than the bank provides -- any time you fire up your spreadsheet. Contrary to my nasty words in past columns, I have found this an amazingly informative and useful computer application.

One of the reasons I used to scoff at those who balanced the checkbook on a computer was that it seemed to take so much time. After all, you had to type in every check. What a pain!

In practice, it's been no pain. I took about 40 minutes setting up the spreadsheet formulas. I sit down and enter checks and deposits every few days. It takes, in total, about five minutes per week. But it saves me the hour or so each month I used to consume in the (often futile) effort to reconcile my records with the bank's. And I think that at about 11:00 p.m. next April 14, I'm going to be extremely happy that I invested the weekly five minutes getting a permanent record of every check in every category of deduction.

In a few years, of course, even that five minutes will be eliminated. Somebody will come along with a device that reads your checks automatically and feeds the information to your spreadsheet.

In short, I'm forced to eat my words. In the eloquent phrase of former Supreme Court justice Robert Jackson, who found himself one day reversing one of his own opinions, "The matter does not appear to us now as it appears to have appeared to us then."