Cold Climate Folks: how often to run your C in the winter?

Once I winterize I don't run the MH at all until spring. I read somewhere that the cold starts are harder on the engine than letting it sit. I do run the genny about every month provided it warms up a bit and I can dig the exhaust pipe out of the snow.

I have a Battery Minder Plus on the coach battery and a trickle charger on the chassis battery.