Infrequent use doesn't help either, since the mechanisms can dry out.

WSJ: It Takes Brass to Play the Wagner Tuba | By Barbara Jepson | The Ring of the Nibelung

It's not just infrequent travelers who get burned, but sometimes road warriors who happen to switch programs and don't pay attention to the old program.

WSJ: Saving Frequent-Flier Miles From the Ax