I have one bike that has studs in it all the time. I can decide if I want studs at the last minute. If there is black ice don't try to ride without studs.
Cold hard flat glare ice is impossible to ride very far without falling without studs. But hard flat ice is the best surface for studded tires to grab. I don't believe that anyone with experience on glare ice would say you don't need studs. The biggest danger on ice if you are on studs, is cars without studs sliding around. Where I live studded tires on cars is illegal.

It's very hard to asses the chances of falling on some ice and some dry pavement, along your route. You have two choices. 1) wear out studded tires somewhat quickly. 2) Or possibly falling and getting hurt, or possibly falling in front of a car if on the road. I have plenty of off road, on lake, or bike path riding available to me. I do it for fun. I have annoyed a couple of skaters when I rode on an ice rink one day. Been using studs on ice on a bicycle since about 1990. Going back to the 1970's for studs on a motorcycle.