The telephone in John Wells' Hyattsville house starts ringing incessantly in January, long before taxpayers face their annual day of reckoning on April 15.

But Wells, 73, a former Internal Revenue Sevice agent, doesn't mind. Those pleas for free help at tax time have been coming for nine years now.

Wells is a volunteer for the Prince George's County Department of Aging, which oversees a network of 50 specially trained "tax aides" who offer senior citizens free help in preparing federal and state income tax forms.

"I've stayed busy with requests right straight through since January," said Wells, who became a tax aide in 1974, a year after Prince George's started the service.

Thousands of county residents 55 and older have used the tax aide program for help with their income tax filings, but county officials say they are receiving an unusually high number of requests this year.

"We're overloaded," said Dorothy Taylor, who coordinates the tax aides, "and I think it's for the simple reason that many elderly people cannot afford a reputable firm to help them prepare their taxes." Some firms offer initial assistance for less than $30, but that price and the cost of subsequent visits are too high for many senior citizens, Taylor said.

In February and March, some 3,500 older county residents took advantage of the program at 17 centers around the county, Taylor said. The tax aides, who include retired accountants, lawyers and military officers, also visit homebound residents, Taylor said. The program costs $3,800 a year to run; tax aides receive some federal funds for their mileage expenses.

In their first two years as volunteers, the aides must complete a three-month training course on taxes paid for by the county and run by a Seabrook accounting firm, Taylor said. In succeeding years, they also must pass a refresher course to keep pace with changes in the tax laws.

Appointments with the tax aides are supposed to be scheduled through Taylor's office, but over the years, some county residents have come to regard certain aides as their own--and call them at home. Wells is one of the most popular, Taylor said.

"A lot of them tell me, 'I want you to help me with my taxes again this year,' " said Wells, who specialized in corporate taxes in his two years as an IRS agent during the 1940s.

An accountant most of his working life, Wells was an office manager for a dance studio and then a comptroller for a group of employment agencies before he retired. He handles roughly 40 cases for the county during the tax season and donates his services to another 30 at the same time.

"A lot of people come back year after year, and I generally oblige them even though we're not supposed to be a walk-in service," said Wells, who also teaches a course on taxes for senior citizens at Prince George's Community College in Largo.

Wells' typical clients are retired government workers, "not indigent by any means, with a good pension that gives them anywhere between $40,000 and $50,000 in annual income," he said. Often, the retirees need advice on taxes on stock transactions, dividends and interest income.

Taylor said that while the aides have counseled residents with annual incomes as high as $80,000, "the program is keyed for the seniors who really need us, the ones who'd be lost without our help."

"The people that we tax aides are helping are wonderful, grand people, real ladies and gentlemen," Wells said. "After awhile you get on a first-name basis with them.

"Besides, it's a good way for me to stay busy," Wells said. "I don't believe in the rocking chair."