DR. WALLACE: Some time ago, an 18-year-old high school graduate wrote to you asking if he should take an offer from a credit card company and apply for a card. You warned him about the high interest rate on the unpaid monthly balance and the importance of paying at least the minimum monthly payment allowed by the credit card company to keep a good credit rating.

That's all well and good, but you should also have informed him that if he only makes the minimum monthly payment on a $2,000 balance, it will take 18 years to pay it off if he never charges anything else during those 18 years. Plus, he will have to pay $2,615 in interest. That doesn't make your suggestion to get a credit card look too intelligent. — Bernard, West Palm Beach, Fla.

BERNARD: Wow! You bring up a startling bit of information. I'm sure credit card companies are not thrilled that I printed your letter.

I still think that credit cards can be useful economic tools, if used prudently. My answer should have been: Yes, obtain the card, but use it wisely. Pay the balance each month, but if that is not possible, at least make the minimum payment, and then pay extra the next month to catch up.

Then I would insert your warning that by making only the minimum payment each month, a $2,000 debt would linger for the equivalent of a lifetime — another 18 years! And the interest you wound up paying would be considerably more than the debt itself.

There — now I feel better!

FOR BETTER OR FOR WORSE IS A MARRIAGE VOW

DR. WALLACE: You said in a recent column that once both parties are over 18, age isn't that big of a deal. Well, it is a big deal. I was 20 when I married my husband, who was 45. When I was 30 and in the prime of my life, he was 55 and he decided to retire from his job. I wanted to go out and have a little enjoyment in the evening and he wanted to stay home, watch television and drink a few beers.

When I was a young woman at age 39, I turned into a full-time nurse for my 64-year-old husband, who had suffered a stroke. I am now 49 and still a nurse taking care of my bedridden husband.

Don't get me wrong. I loved him when we got married and I promised to love him in sickness and in health. I kept that promise. But, would I marry someone 25 years older than I if I had to do it all over again? No way! In fact, I wouldn't marry anybody more than five years older than I. Marriage should be a fun partnership, not a study in geriatric care. — Hazel, Batavia, Ill.

HAZEL: Thanks for sharing your life's story. When there is a large age gap between spouses, the likelihood of the kind of problem you describe certainly increases, and your words may make other young women think twice about marrying someone a great deal older.

However, while your husband's health breakdown is unfortunate, such a calamity could happen in any marriage. That's why the "for better or for worse" part of the marriage vow has meaning.

Dr. Robert Wallace welcomes questions from readers. Although he is unable to reply to all of them individually, he will answer as many as possible in this column. E-mail him at [email protected]. To find out more about Dr. Robert Wallace and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.