The NFL is increasingly turning into a young man's game. The average snap-weighted age (SWA) in 2017 was 26.46 years, which just breaks the record low set a year ago at 26.55 years. The age could go down even more in 2018 if Adam Vinatieri (46 this season), Tom Brady (41), and Terence Newman (40) ever hang it up for good.
The differing roles of those players serve as good examples for why we calculate a team's age based on how many snaps each player played in the regular season.