Owl of Purdue states: “In other words, every time you bring up the author in a new paragraph, you should use the year, but you don’t have to within a paragraph, as long as it’s clear from your wording that you are discussing the same author. If you were giving a direct quotation that needed a parenthetical reference for the page number, then you’d include the year as well.”
Remember, if you list the author in parenthesis, you must include the year.