When dressing male clients it was recommended that any business shirt should never have a pocket as a businessman is not a tradesperson and therefore should have no use for a pocket in his shirt. The more rugged the trade and the more the man will move will dictate whether the pocket requires flaps and even buttons.
Chest pockets on shirts became common in the 1950s and 1960s as a result of the decline of the waistcoat. The chest pocket provided a convenient location to store cigarettes, pens, and other small items. In the 1950's pockets were added to t-shirts in the rise of the t-shirt going from underwear to outerwear.