For example, General Medicine is three years and sub-speciality in pulmonary, nephrology, or cardiology can be two or three years. General Surgery is usually five years-six in some research oriented universities. This can be followed by a surgical sub-speciality of one, two or three years. In general, incomes for highly specialized physicians is higher than for general physicians. Incomes vary greatly depending on field and how much is research, teaching, charity work etc.
Incomes also vary greatly with location-rural areas usually less and cities more.
My advice to students considering medicine has nothing to do with time or money. Like most professions enter it because you have a passion or desire to be in that field. These students are always the most successful. Enter for the money and you'll earn every nickel. I will soon be writing a term paper on the topic of anesthesiology.