Like the OP, I started watching the first team in March '66, (Leicester FA Cup), got my first S/T for 72/73 season and started doing fairly regular aways in '75. I would think I've averaged around thirty-odd games a season over that whole 56 years, so approx. between 1600 and 1700 matches altogether.
Back in the 80s I started working out how much I spent in a season on football, I can't remember the total but even though it was a lot cheaper in those days it frightened me enough that I haven't done it since!