Like most things in life, "it depends."

I can easily remove my Husker Du tires from my rims without any tools whatsoever, so there's no need to bring levers.

In regards to dealing with flats--if you get one, and considering the volume of air you need to get a fat tire up to even a couple of PSI, what do you think your chances are of being able to reseat and fill a tubeless tire with an on-bike pump, while freezing your hands off?

Personally, during the winter I'm never far from a road and an easy call to get a Ride Of Shame home, so I don't bother to bring a pump or spare tube. If I didn't have that option, I'd *definitely* bring a pump and tube.