It's a foregone conclusion in the National Hockey League that productivity declines with age. Dave Lozo used the lens of Alex Ovechkin to call our attention to this inevitability, using the "enjoy it while it lasts" pathos.
But within the same organization, there's another player, older than Ovechkin, whose previous team success—made possible in no small part thanks to his personal dramatics—has given him a pedigree unlike any other in the room. Speckles of silver in his hair though no longer donning a silver sweater, Justin Williams is four years Ovechkin's senior, three Stanley Cups highlighting a pedigree that features more Game-7 victories than the Ovechkin-era Capitals feature Game-7 losses.
Twenty-three games into Williams' 17th season in the NHL, his productivity shows no signs of slowing down. Here's a look at his rate scoring numbers dating back to his 23 year old season, which is as far back as the data is available.
(data from War On Ice)
You can see that Williams is a paragon of graceful aging. While the overall trend here is down-and-to-the-right, Williams is still comparably productive at lighting the lamp, and falling off a bit at collecting apples. His overall P/60 at 5v5 is currently an improvement over his final two years in LA (sample size caveats acknowledged), but goals aren't only scored at even strength. Let's take a peek at Williams' all-situation production over time.
Justin Williams is actually producing points at a rate that ties his 2010-2011 career best, when he was a spritely 28 year old.
Williams' consistency doesn't only apply to the scoresheet. The man who's earned the moniker "Mr. Game 7" has been a possession Messiah his whole career, the season to date included.
In 2012-2013 and 2013-2014, Williams had two of the best possession seasons of his career (on two teams that led the league by that measure), but he's still driving play with same efficacy that he did in his early twenties. If the platinum hits of Williams' legacy are his playoff heroics, the B-side is his asininely good possession numbers, which show no real sign of slowing down.
Williams has spent the bulk of his inaugural campaign in the District on the second line (where, frankly, he belongs), but has done some spot duty on the third line as well. With skill guys like Nicklas Backstrom, Evgeny Kuznetsov, and Marcus Johansson sharing the bulk of Williams' 5v5 ice time, it might be easy to presume Williams the passenger here.
That's not the case, as evinced by the below.
All three of Williams' most common comrades see their possession numbers dip dramatically when they take the ice without him. Using John Carlson and Matt Niskanen as proxies for the first and second defensive pairings, we can see that this trend holds true amongst the Caps' best blueliners as well.
It's also worth noting that Williams' possession magic seems to apply even to noted possession anchors Jay Beagle, Jason Chimera, and Brooks Orpik. All three are on the wrong side of 50% without Williams, but get over the hump with him. Really, there isn't a single player it doesn't apply to. Thanks to a lot of hardwork and creativity from Micah Blake McCurdy (check out his amazing work at hockeyviz.com), you can see the ubiquity of Williams' on-ice impact across the roster.
When the Caps signed Williams, they thought they were getting a top-6 forward who drives possession. With the season a little over a quarter through, Williams has given his new team no reason to believe they're getting anything less than they thought they would.