I was a sales rep for a major company calling on Grocery wholesale warehouses and large retail stores in North East Tennessee, Kentucky, and North Carolina.  Most of the company vehicles in this area used this setup. A aggressive tread snow tire was mounted on the spare wheel.  Another wheel was purchased and the matching snow tire was mounted on it.  When snow was predicted, the spare and addition wheels with snow tires were mounted on the car. One original wheel with a summer tire was put in the trunk.  The other wheel with summer tire was stored in my basement at home.  In the spring both summer wheels and tires were remounted on the car. One snow tire became the spare and the other wheel/snow tire went to the basement. This allowed me to wait to the last minute to put the snow tires on the ground. (The traction was good, but the noise was irritating). the odd summer tire stayed in the basement as a replacement if one on the car was damaged.