How often do you guys start your car over winter storage?

I live in east central Indiana, and my cars are stored inside my insulated, but non-heated pole barn. I put Stabil in my gas tanks in November, and then start the cars maybe one or two times in the December - February timeframe. I let them run long enough to open the thermostats. In March, I start to do seasonal maintenance and maybe a cruise or two by April if the weather is good.