The other night I heard a great deal of fuss emanating from the kitchen.
Poking my head around the corner, I noticed my spouse was in the midst of mixing a batch of chocolate chip cookies (yum), however, after 10 years of faithful service, the electric mixer that she was using had decided at that moment to cease functioning.
The mixer was still making the appropriate noises that you would expect, but the beaters were definitely not beating anymore.
Initial diagnosis - stripped gears
After finishing mixing the cookie dough the old fashion way and doing some quality control testing of the resulting cookies, I decided it was time to take a look at the mixer and find out what really killed it.