It seems like overkill to put studs on in the winter, but studs have given me more cycling options.
You can always take the main drags, but riding through waves of slushy-salty snow, and dodging the cars that seem to think the roads are bare and dry, is not really my idea of cycle-fun.
So what are the options? Taking the sidewalks? That's even more fun when they are narrowed by snow piles. Bike lanes? That's where the plows push the snow. The spaghetti-like routes of the suburban sideroads will get you there someday and will avoid the traffic, but the checkerboard of hard-pack snow and sheets of ice on poorly serviced sideroads is dodgy riding for the best of treads.
My answer for all conditions is studs. If I'm forced to suddenly go from plowed pavement to snowy margins (cause some motorist was making it tight for me), I feel as if I have sufficient control. On those night trips home, where the roadway is so poorly illuminated that I'm never sure what I'm about to hit, I breathe easier.
Yes, the good studded rubber is expensive. I buy cheap (who would have thought?) and don't put them on until I absolutely have to, and take them off once it is pretty likely I can avoid the last few snow days. May the tread be with you.