Is it common for most men to shave armpit and pubic hair?

Local habits. There is no medical/hygienic reason to shave; not for men, nor for women. That being said, cultural, geographic, and atheletic norms vary. Men who are swimmers often shave all of their body hair and sometimes their scalps to improve aerodynamics.

Related Questions

Is armpit and pubic hair one of the reasons for that men smell?

Yes and no. All adults have a natural odor, differing some between the genders and between individuals. There are special glands to produce it, especially in armpit and groin, and the hair may hold the scent somewhat, though shaving won't reduce it much. Read more...