Suit and waistcoat button essentials
Jacket: There are two types of double-breasted and single-breasted. When wearing a double-breasted jacket, you generally have to button all the buttons, and sometimes you don't need to button the bottom one. For single-breasted jackets, one or all of the buttons below may not be buttoned. Do not button all the buttons. Horse clip: The lower button is often left unbuttoned. If you wear a tie, it should be placed inside the vest, and be careful not to expose the tip of the tie. In formal occasions, three-piece or two-piece suits should be worn, and woolen vests or sweaters should be avoided.