What are your favorite/most used trucking related apps?

Probably posted in the wrong section, but I will answer from my perspective anyway.

With my ThermoKing APU, no you don't "need" to have 12 volt stuff, as the truck has an 1800 watt inverter as part of the package. On the rare times when I have had issues with the APU, I was still able to power my laptop, microwave, etc.

I had a Carrier APU prior to this truck and it was completely different. There was not a separate inverter but there was still household-type plugs in the truck. The problem was when the APU was down, you lost all power to the plugs. Our Carriers seem to break belts on a semi-regular basis.

Another problem relying strictly on household applicances is in the event you have to get in a temporary truck (rental or a loaner company truck that does not have an APU).

I have had the unfortunate circumstance of getting in to rentals and company loaners (not a contractor, just a company driver having to use another company truck for a few weeks while mine was down for repair). I don't take the microwave, but I take the laptop. In cases like this, I have a small plug-in power inverter (150 W) that powers my laptop and USB charging needs.