How many days per month is a sickle cell anemia person feeling well?

Hard to tell. There is sickle trait with anemia usually remaining care-free. The anemia is detected incidentally through a lab test. The anemia of sickle cell disease is different. You can have months feeling O.K. Till an infection, cold episode or a clot....Which intiates the sickling and hemolysis of blood. Be positive. Get connected with sickle cell doctors, organizations, societies, patients or relative.
Varies widely. There is no easy answer. The disease can be very different in different people, and there are variants of sickle cell anemia that behave very differently.