When wearing a suit or sports coat, when is the appropriate time to fasten the bottom buttons? The answer is that 99.5% of the time, never; but there’s always margin for error or that exception to the rule. You have King Edward VII to thank for this more comfortable approach to suiting up.
King Edward VII, also known as Bertie, son of Queen Victoria (1814-1910) became so heavy in life that he could not button the darn tootin last buttons on his vests, coats and jackets. Or it could’ve possibly been that he might’ve just not seen them due to his bulging stomach. Regardless, his subjects began to follow their majesties lead and left their bottom buttons undone as well. So thanks to Bertie’s eating habits and need for more comfortable attire, the trend still sticks today.
Most single breasted suits have one to three buttons. Two and three buttons are classic cuts while one is a bit more fashion forward and more suitable for social times than business times. Fastening the top two or the middle button in most circumstances is acceptable. If there is a fourth button, unfortunately it was probably made for all of them to be buttoned up, even that lousy fourth one down.
Double breasted suits are deemed more formal and usually have four to six buttons. They are often identified in a number such as 4/2. The first number gives the total number of buttons and the second gives the number of functioning buttonholes. Button accordingly.