We have a GE built-in microwave above the range and all of a sudden the
cooking times needed to heat food have drastically increased. Is it
possible for a microwave to gradually wear out? This unit is only 7 yrs
old. I was under the impression, they either heated or didn't, and didn't
think there was an in-between.

Anyway to check it?
Any thoughts?

Tired of 10 minute, lukewarm leftovers!

Thanks,