New England Patriots head coach Bill Belichick said a lot of interesting things in NFL Network's "A Football Life" documentary that chronicled the 2009 season, and one that really stood out was his comments about coaching past age 70.

"You definitely miss a lot during football season, family stuff, holidays, kids stuff when they're young, and their games. The world passes you by," Belichick said during a car ride toward the end of the documentary. "I have a hard time picturing not coaching football, at this point. I won't be like Marv Levy and coach in my 70s. You don't have to worry about that. Fortunately, that's a few years off. I enjoy doing what I'm doing. I don't think it's going to last forever. It beats working."

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Levy coached the Bills until he was 72. The oldest head coach in NFL history was Romeo Crennel with the Houston Texans (on an interim basis) in 2020 at age 73.

Over a decade has passed since that documentary was aired in 2011, and Belichick is still coaching despite winning three more Super Bowl titles during that span. Belichick celebrated his 70th birthday in April, and on Sunday he'll begin his 23rd regular season as head coach in New England. His kids are much older now, and two of them, Steve and Brian, are on the Patriots coaching staff.

And judging by his comments on the subject in recent weeks and months, it doesn't sound like Belichick is planning to step away in the immediate future. 

In fact, if Belichick could do that part of the documentary over again, he probably wouldn't have talked about not coaching into his seventies.

"I wish I hadn’t said that,” Belichick told The Boston Globe's Dan Shaughnessy in a phone interview earlier this week. “I was probably thinking of what I would feel like. Now, there’s what I actually feel like, and those are two different things. That was not one of my better statements."

In regards to retirement, Belichick takes the approach he does as a coach with his players: Just worry about what's in front of you, not the future.

"I get the question occasionally,” Belichick told Shaughnessy. "I don’t really think about it. To me, it’s about this year. Worry about next year next year. I don’t really think about next year or five years from now. I’ve got a lot of work to do trying to help the team any way I can and make us a good, competitive team, which I think we are. But we’ve got to prove that."

Retiring can be hard, especially for someone like Belichick who obviously still loves football, coaching and the thrill of competition. And while he's made mistakes in recent years, both in terms of coaching and roster construction, the post-Tom Brady era hasn't been awful. Going 7-9 with Cam Newton at quarterback in a pandemic year, and then winning 10 games and securing a playoff berth with a rookie quarterback isn't too bad at all.

All good things do eventually come to an end, but with Belichick still going strong, it's hard to predict when that time will arrive for him and the Patriots.