A server system includes an acquisition section, an estimation section, and a recommendation display control section. The acquisition section acquires measurement information on a target user related to a body part where the item is worn. The estimation section estimates, based on the measurement information, a first recommended size that satisfies a predetermined comfort level condition during a first comfortable period when the target user wears the item. The recommendation display control section performs recommendation display control to display a first recommendation display indicating the first recommended size on a terminal apparatus.