If the temp is above 45, then I wash the car myself. I have a lot of grass in my backyard so I move the car on to the grass (if there is no snow) and wash it, then move it into the garage. I wash it on the grass so my driveway does not turn into a sheet of ice. I try to wash as often as I can because they use tons of salt around here, and I dont want it sitting on my paint.
If I cant wash it myself I go to a touchless pressure washing place. I go every 3-4 days to spray the crap off the car until the temp gets to where I can wash it myself.