Facts. We summarize the trial judge’s findings of fact. Casey had been a tenant of York since October, 1989. She resided at Presidential Acres, a large apartment complex located in Randolph. Initially, her tenancy was under a lease, but she continued as a tenant-at-will, paying rent of $920 per month.2 Casey did not pay rent for July, August, September, and October, 2001, leaving a balance due York of $3,680. She was served with a notice to quit for nonpayment of rent on August 17, 2001, and a summary process complaint on September 5, 2001. On September 4, 2001, York received an unsigned letter, dated July 21, 2001, from Casey or from someone acting on her behalf, complaining of several problems with her apartment.3 The letter claimed that Casey was having problems with dryer-vent odors, leaky windows, bathtub drainage, a tom linoleum floor, ant infestation, a noisy refrigerator, cracks in her walls, and a leaky toilet. The Randolph board of health conducted an inspection of the premises on September 8 and documented several of Casey’s complaints. A list of these itemized and documented complaints was sent to York. A reinspection was conducted on September 22, and the board of health found that York had made all the requested repairs with the exception of some remaining cracks in the walls, some dirt falling from a bathroom ceiling fan, and some evidence of ant infestation. York replaced the kitchen floor, replaced windows in two *746bedrooms, installed a new refrigerator, sanded and repainted the walls, repaired the toilet, replaced the motors in the ceiling fans, and twice exterminated for ants in Casey’s apartment and in the entire building.