All that one needs to know is a cheap set of winter tires is better in winter than any all season (3 season) set, period. The End. Don't cry about cost. Most insurance companies offer discounts if you have winter tires. That discount will cover the cost over a number of years. Winter tires will stop (on average) 30% sooner or 30% less distance than 3 season tires. Just ask yourself "what's my life worth?" Quebec got it right making it law. Must have winter tires on from Nov 15 to April 15. They recorded 5% fewer fatalities and a lot less injuries......  speaking from experience once you drive with winter tires in winter you'll never go back to 3 season tires.