Do doctors see a lot of patients with frostbite?

Yes. We don't always recognize the problem however, see your primary provider to further evaluate.
Not typically. Fortunately this is not common but it is not rare and obviously occurs in colder climates where individuals may be exposed for a variety of reasons. Treatment requires gentle rewarming of the effected body part.
Depends. On what's considered "a lot" and where yous are in the world. How would the answer to this help you?