My HO on studs: ideally you would have two winter wheelsets; one wheelset with studs for icy conditions. one wheelset with 2.1-2.4 knobbies for all other winter conditions.

Studs work great in the ice, but provide little to no benefit in deep snow. Studded tires are heavy and have huge rolling resistance on the pavement, which I hate. I find myself using studs during the typcial 1-2 week window when the roads are glare ice around here. Then I take them off when there's snow, or when the ice melts.

I know guys that run studs until spring, but I just can't justify the rolling resistance, not to mention the expense of replacing studded tires when they were out. I have Nokkians and they actually wear pretty well; I've been running the same set for 3 winters and the only damage I've done to them is while riding over boulders that weren't icy. The carbide studs are so hard that they grabbed the rock and tore themselves out. Now I have missing studs.