I usually put Schwalbe Marathon Winters on my primary bike (Workcycles Opafiets). If things are mostly clear (more and more each year as clearing of bikeways improves) then I'll pump them up for a smoother ride, otherwise lower pressure for better stud contact.

We have some Omafiets (Workcycles, Batavus, Gazelle I think) for guests to use so if things are really clear I'll ride one of those.

This year I switched it up and put the studs on only the front of one of the Omafiets for me to use when needed and ride my Opafiets when I know things are clear and will be on return as well.

My wife's bike always gets studs front and back. She'll occasionally grab one of the Omafiets if she's 110% sure that she'll not encounter any ice.