I have several Rancos, only one of which is 2-stage. Since the ambient temp in my basement where I have my fridge ferment chamber doesn't swing much, I generally use a single stage for fermentation, along with a thermowell, to run the fridge in summer, and to power a Fermwrap heater taped to the back of the fridge in winter. And the fridge door normally stays part way open at times during the ferments in winter. Sometimes the temp in the basement is just right so that I can ferment in a spare basement bedroom!
Anyway, I have lost 2 or 3 Rancos, normally during thunder storms so be absolutely sure to use a good surge protector since in my experience the Rancos are pretty sensitive to power fluctuation.
Also, I highly recommend that you reset the Ranco's temperature so that it is not powering your equipment before powering it off and/or disconnecting it. Another good reason to use a surge protector with an on/off switch, as secondary insurance whenever you have to turn off, or especially if you have to unplug your unit.
If you don't do this, it is possible that the unit will go into error mode from which it either won't recover, or will recover partially and be temperamental from that time on.
I don't set my kegerator chest freezer to on/full, so that in the event my temp controller failed on it, it would take longer to freeze all the beer inside, maybe giving me a bit more time to notice the failed unit before all freezes hard. I like to use electronics, but I also check my temp controllers regularly (when getting my first pour of the day or if in the basement once per day) to ensure they are operating as set and desired.
Also, if using a thermowell, be aware that with the new ones I've found on the market, they recommend that you actually sand or slightly shave the Ranco's probe, otherwise it won't fit into the thermowell. Guess that's why I always use my older model thermowell. Go figure!