Suits are expensive. A young man who expects that he will need to wear suits later in his career should begin building his wardrobe before he needs it so he will not be faced with purchasing too many at any single time.
Every man should own the basic charcoal and navy solid suits in a medium weight wool when he enters the work force. And then the clock begins ticking. In most professions, he will have several years when business casual dress suffices most of the time, before he finds himself in client-facing positions that require him to dress more formally.
Suits wear comfortably within a range of thirty degrees F (half that in Centigrade), and a man should ideally have at least one suit for each day of the week that he wears one, times two seasons if necessary for his climate. And he should add a sixth suit for each season if he is suited every day. This means the young man has three or four years to acquire as many as ten more suits.
Assuming he lives in a temperate climate, begins with two mid-weight suits and acquires ten more, I suggest our man first purchase two more mid-weight suits, and then two for the season (spring or fall) that his mid-weights are least suitable. Once he has six, he should alternate spring and fall suits after that until he reaches his targeted dozen.
Suit acquisition is a career long routine. It requires about three suits a year to stay ahead of wear and tear, and, like the young George Hamilton in the photo, men in the public eye may feel the need for half a dozen or even more of them annually.
That is how the tailors stay busy.