The 2017 NBA trade deadline is a reminder of a universal truth: Assets can depreciate.

Boston Celtics general manager Danny Ainge has assembled the NBA’s most expansive collection of assets, including Brooklyn’s unprotected first round picks in the 2017 and 2018 drafts. Yet after months of rumored trades involving star players such as Carmelo Anthony, Jimmy Butler and Paul George, the Celtics stood pat at the NBA trade deadline.

Meanwhile, in Philadelphia, home of former general manager Sam Hinkie’s Process, the 76ers traded former sixth-overall pick Nerlens Noel to the Dallas Mavericks for Justin Anderson, Andrew Bogut (whom the Sixers are expected to buy out) and a top-18 protected first-round pick that can — and likely will — turn into two second-round picks next season. Anderson has the potential to be a useful player, but it’s a scant return for Noel, who was once a potential No. 1 overall pick but has struggled to find playing time in a crowded Philadelphia frontcourt.

Independently, both scenarios make sense. For Boston, George reportedly made it known that he is intent on joining the Los Angeles Lakers if he can’t contend for a title in Indiana, while Chicago was reportedly hesitant to enter a full rebuild mode by trading Butler. And for Philly, it was reasonable to move Noel given the limited trade market for center Jahlil Okafor, and the necessity of making room for Dario Saric and Ben Simmons, who could return from a foot injury after the All-Star break.

But the teams’ quiet deadlines are also the results of Boston and Philadelphia attempting to press pause at specific moments in their cycles of success: Philly spent years lingering at the shank end of the standings to collect draft picks, and Boston has kept its powder dry, demurring on trades for its most valuable pieces rather than pushing all-in and committing to a specific title window. As Zach Lowe has pointed out, the Celtics have not exactly been risk averse over the years, but they remain picky about which deals they will pull the trigger on. While that sounds good in theory, NBA teams can’t actually stop the passing of time, and the value of their assets has begun to shift under foot.

Both teams seemed to have grander ambitions than holding steady and waiting for next year. The Celtics are the 2-seed in the east, and have a chance, albeit faint, at knocking off the defending-champion Cleveland Cavaliers if injuries to Kevin Love and J.R. Smith linger. But adding a player like George or Butler (or even Carmelo Anthony) is the most realistic path to actually challenging the Cavs and Golden State Warriors for the title, especially since the best prospects in this year’s draft are guards and Boston’s backcourt is already overstuffed.

The 76ers remain a very bad basketball team, but with Joel Embiid looking like the real deal and Simmons expected back soon, the timeline in Philly has finally progressed to the point that it’s time to attempt to convert a glut of assets into a functional roster. While failing to carry through on those ambitions is not a deathblow to either team’s long-term plans, it does serve to remind that both are on the clock.

This is likely a more pivotal moment in the teams’ development for Boston. In the same way a key role player — say, Tristan Thompson — has far more value to a championship contender than a lottery team, draft picks provide different uses to teams at different stages of development.

For any team, a first round pick is a chance to replenish the roster and plug obvious needs with young players on below-market contracts, or trade bait for teams in need of that sort of player. And of course there’s the chance to find a superstar player, either at the very top of the draft, or further down the line with prospects like Kawhi Leonard or Paul George or Rudy Gobert.

But for a team like Boston, with a deep, young roster and few obvious needs besides star talent at the top of the depth chart, cheap, half-decent labor doesn’t really have the same value. Any role that could be filled by a young, cheap draft pick is already being filled by a player fitting that description. Ironically, this makes draft picks less valuable to the sort of team that tends to hoard assets, especially if they can’t trade them away. In the last few years, Boston has not been able to find those trades.

In the 2016 draft, Boston used its three first-round picks on Jaylen Brown (No. 3 overall), Guerschon Yabusele (No. 16) and Ante Žižić (No. 23), and selected five more players in the second round. In 2015, it selected Terry Rozier and R. J. Hunter in the first round and had two additional second-round picks. Those aren’t necessarily bad picks, but as picks become players, their value shifts. Picks made by Boston are made with Boston’s needs in mind, and that makes the resulting players less valuable to other teams than the chance to make those decisions themselves.

The less theoretical problem with amassing draft picks on a team like Boston is that there aren’t many minutes for the draftees to play and develop. That also turned out to be the case for the position-agnostic approach in Philadelphia, where neither Noel nor Okafor has been able to find a consistent role. And as we saw at the deadline, it’s hard to get good value for a young player who doesn’t play very much.

None of this is to say the Celtics or Sixers did anything wrong this deadline. Ignoring the value of future assets in favor of locking down known entities, even if those entities are known to be flawed, is how you get the Knicks trading away their future for Eddy Curry. But the countdown is ticking on the advantages they hold, regardless of whether the teams find the perfect trade or not. So it might be time to begin looking at imperfect deals rather than letting many more assets reach their sell-by dates.

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