What size circuit breaker?
I'm about to ask an electrical question which for me is akin to being grossly overweight, old, bald and naked in public (sounds a bit like me actually, sans the "in public"). I was most impressed and convinced when I heard the "little gremlins" explanation to all things electrical. Heard it, believed it, and moved on.
I'm about to install a 12v cig lighter and dual USB 5v (2.1 amp for the USB) power port. I will be charging my phone on one of the USB's. I will likely use the 12v cig lighter for powering my emergency mini air compressor. Who knows what else. I can look up the specs for the compressor, but given the disparity of types of devices I might use, maybe multiple at once, I don't know what size circuit breaker to use. I don't know how bad/dangerous it is to have an oversized breaker. I think I can get my mind around the wrongness of too small of a breaker, but then again...those damn gremlins!