From my relative short experience of driving in snow in Denver, 10 years, all-seasons work better the newer they are... as they get older and the rubber hardens, they don't bite as well... so its a gradual thing... luckily for us here at altitude, we dont' see much ice when it snows, very dry conditions with sticky snow is the norm... snow tires are typically overkill for those of us that are just commuting in town... going to the ski slopes every other weekend, its wise to get a tire with more aggressive tread that doesn't harden in the cold conditions.... For those days, we have our FJ cruiser with Pirelli Scorpion ATRs which pretty much makes 4wd obsolete...