The program runs from Feb. 1 until the tax deadline, which is April 16 in Massachusetts this year because of the Patriots' Day holiday. Federal returns are due April 15.
Each year, the volunteer tax counselors participate in mandatory training and must pass an exam for IRS certification. They meet with clients at community centers, libraries or other public places.
Their work is checked by another counselor before the returns are filed.
"It's well-structured, and there are a lot of good resources," said Marty Maffeo, 64, of Natick, who began volunteering with the Tax-Aide program four years ago after retiring as an account executive for an investment firm.
Help finding tax credits
Maffeo said an important part of the job is helping eligible residents apply for the state's Senior Circuit Breaker Tax Credit for homeowners and renters age 65 and older who meet certain income and other eligibility requirements.
The credit can be substantial: For 2012 it was a maximum of $1,000 per year, and it can be applied retroactively for up to three years.
Sonnenschein said she was aware of the circuit breaker credit but hadn't applied for it until a Tax-Aide counselor helped her.
She had always prepared her own returns until she realized it was taking her longer to complete them, and her confidence was ebbing. It was then that she decided to turn to the Tax-Aide program.
For the past few years, a Tax-Aide volunteer has helped Sonnenschein file the returns electronically. She loves the convenience.
"I don't have to wait in line to mail my returns," she said.
To find a site or make an appointment with a volunteer tax preparer, enter your ZIP code at the AARP Foundation Tax-Aide Locator website or call 888-227-7669 toll-free.
Jill Gambon is a writer living in West Newbury, Mass.