My background is in the manufacturing and testing of golf balls. Golf ball initial-velocity does degrade with time (about 1 yard for every feet/second loss). The environment the golf balls are exposed to will have a direct impact on, what I call, "performance loss factor". For instance, a hot and/or wet environment will have the highest "performance loss factor" on golf balls.
Having said that, most high handicappers will not be able to discern performance loss on "refurbished/old golf balls" due to their lack of distance/dispersion control of their shots.
