1997 Honda Accord alternator keeps going bad

1997 Honda Accord LX mileage:170,000. We purchased a used Honda about a year ago for our daughter. One meticulous previous owner with a little black book with all records kept it in great condition. About two months ago, the battery light went on and then her car went dead. We jumped it a few times and got it in for a check. It was the alternator and we had it replaced. Less than a month later, the battery light came on and it was the alternator again. The parts distributor replaced and even reimbursed half of the mechanic's fee. They checked the battery, and it was fine when I had the service done and the new alternator put in. Again today, the light went on. It has only been two weeks! What in the world is happening? I am afraid to let her drive it. Other than that, the only thing I have had replaced was the ignition switch in January. I