I took my snows off mid-April two years ago and then promptly slid into a curb in the Squaw parking lot and broke (more or less) the front axle; no body damage. It was ridiculously slow-moving and a $500 deductible. And you have to fill out all that paperwork for the state when you have a "collision." The tires on the car were a Cooper touring something or other.
Anyway. I ran Nokain Nordmans for 3 seasons on my old vehicle, from November before Thanksgiving to mid-late April, although the year I broke my leg, I took them off in May or June. I felt invincible in them and once drove around 4 spinouts at the Sugarbowl exit on 80 with no problem. Like
@Banzaibikes, I'm based in Sac. With my new car, I am running Nokian WRG3s full-time, which half the mechanics here call snow tires. At one point when I had the dedicated snows on, I had an incident on a local road where a car at a dead stop in the left turn lane pulled out in front of me as I was going ~50, and the extent to which I had to hit the brakes and not hit them scared the crap out of me. I left
a lot of rubber on the road. There are other reasons I'm not doing the tire swap thing, but the stopping distance on dry pavement in temps > 45 degrees is a factor.
It took a bit of effort to find both sets of tires as no place local had them stocked. The WRG3s I ordered on my own, and I'm sort of surprised that everything worked out.