It is sometimes said age is just a number, and that might be true for the NFL's ageless wonders such as Tom Brady, 40, or Drew Brees, 38.
But for most mortals who play in the NFL, age is significant. Get to 30, and diminishing skills and inflated paychecks will push players out of the league.
Age matters for teams, too.
A young roster is cheap, filled with players on minimum-salary rookie contracts and little ability to dart elsewhere in free agency. The future might be bright, but some of the NFL's youngest players get sidetracked.