I have a 30-year-old Frigidaire upright freezer in my basement. I'd been assuming for a while that it's wasting power due to leaked refrigerant or some such, but I borrowed a power logger from work, and whadda ya know: it's actually reasonably efficient.

The thermostat is dying, so I picked up one of those thermostat plugs with a probe on a wire. Gonna keep it as long as I can. (Plus it's the perfect size for its space, and they don't make that size any more.)