Professional Football Researchers Association Forum
PFRA is a nonprofit organization dedicated to the history of professional football. Formed in 1979, PFRA members include many of the game's foremost historians and writers.
Wikipedia lists John Carney as playing in 4 decades [1987-2010]. Since there wasn't a year zero many argue that we count decades wrong [as in the 80s should be 1981 to 1990] so then Brady would have 4 decades counting it that way but Carney would not. I just go along with what is normally considered a decade [as in 1980 to 1989].