IIt’s Christmas Day and a scrum of journalists surrounds a smiling, exhausted LeBron James in the visitors’ locker room at San Francisco’s Chase Center, minutes after the latest installment in a decades-long catalog of thrilling battles with his friend and foe Stephen Curry. James is asked what he thinks the “good” thing about the league is on any given night, given all the recent discussion about the state of the NBA as an entertainment product. “LeBron and Steph,” he shoots back, grinning. And he’s not wrong. But there are only a few days left until December 30, which marks his 40th birthday, and the four-figure elephant in the room casts a somewhat melancholy shadow over the joy of playing basketball at a high level. No one, perhaps not even James, knows exactly how much time he has left in his illustrious NBA career. But it’s not much.

Since returning from a still-mysterious nine-day excused absence from the Lakers a few weeks ago, James is back playing the aforementioned basketball at a high level after a rocky stretch early in the season. For perhaps the first significant time, James showed real, significant decline during that stretch, posting his worst shooting numbers since his rookie season more than two decades ago. His recent return to form calls into question whether this regression was less a sign than an aberration, perhaps brought on by fatigue after a summer of intense (and hugely entertaining) Olympics en route to his third gold medal. But coincidence or not, it shed light on a topic that has loomed ominously over every step of James’ career in recent seasons: his impending retirement, which he has repeatedly hinted would come sooner rather than later, and the cavernous one , football-sized hole left in his wake whenever he decides to hang it up.

Even Curry, who at 36 is several years younger than James, has been expecting to die in basketball lately. He told ESPN’s Malika Andrews in a recent session that he has been thinking about retirement “more recently than probably before.”

He went on to tell Andrews: “It’s okay to accept and acknowledge that the end is near, but only because it allows you to enjoy what’s happening.” But I think the more you talk about it and the more you acknowledges it, the more it reinforces the sense of urgency in the moment.”

All in all, both Curry and James are still playing at a top-15-20 player level, as evidenced by their Christmas showdown. But the clock is ticking. Should James return next year to play another season, there is strong speculation that it will be his last, and his then 23 seasons will be the longest in NBA history, surpassing Vince Carter’s most seasons ever played . From a fans’ perspective, it’s obviously difficult to balance gratitude for the time their favorite stars have left on the floor with the looming fear of losing them. And for the stars themselves, there’s an even more difficult balance and an age-old question: When should you hold on and when should you let go?

I asked James’ coach, JJ Redick, a former NBA sharpshooter with an impressive playing career, when he knew it was time to quit and how difficult it was, considering the nature of basketball A big part of it is his identity. He particularly remembered a few moments when he realized the end was near.

The first time was on New Year’s Eve of his final year in the league in Dallas, lonely and missed by his family (who remained in New York City all season). “(I remember) calling my parents and just being emotional, talking to them and saying, ‘I just want to get in my car and drive back to New York,’ and my mom said, ‘Why don’t you go ?’ and I said, ‘Because I can’t let go.'”

Redick also remembered another phone call that made him realize this was the case Really Time to call it. “The moment I realized it was over, I was in Dallas, and during that season I had only really seen my family for about four or five days, it was like three different occasions. And one of them was that they came to Dallas and Rick (Carlisle, then Mavericks head coach) found out that they were in town for the weekend and we were playing back-to-back Saturday and Sunday. So I do a shoot on Saturday, come back to the apartment and get ready to hang out with them. I think we went to the science museum or something. And Rick calls me and says, “Hey, I just found out your family is in town.” You probably won’t be playing tonight, and I know you haven’t seen them. Why don’t you just invite her to dinner?’ And I said, “Rick, you’re real, I appreciate that,” and hung up and started crying. I thought, ‘I’m done.’ When the time comes, I’m done.'”

But LeBron James doesn’t want to let it get that far: He has always made it clear that he doesn’t want to play long past his prime. The future Hall of Famer, a one-ball first-round pick, has no interest in overstaying his welcome and has stated multiple times that he doesn’t want to “cheat the game he loves.” But he’s in an interesting environment where he’s certainly still far better than most of the league, still capable of beating the best of the best in any game, but he’s starting to see the weakest writing on the wall to recognize. For someone for whom basketball is his everything in every way Life, It’s an almost impossible question to know when to walk away.

I recently asked James if, amid all the retirement speculation, he had had the opportunity to understand how rare it is to play at the level he is believed to be, given his age. “I didn’t,” he said. “It’s just pretty cool that with the amount of miles I’ve put on the tires and the lack of tread they still have, I’m still able to go up and down the highway and do that at a high level.” He spoke about the level of dedication required and reiterated his previous views on his desire to give up before a drastic decline: “I think I just try to give it my all outside the game for the game before the game begins at all, if that is possible.” Meaning. So I arrive five hours before the game and I’m already starting to do everything I can to put myself in a position to give my best when the fans are here, when the ball has dropped and everyone is going crazy. The man above blessed me with an extraordinary ability from the start, and then I just took full advantage of it. I didn’t want to disrespect what he gave me and we’ll see how long I can do this. But I won’t do it until the wheels fall off. I’m telling you that. I’m not going to be one of those guys.”

He’s certainly not “one of those guys” yet. At forty years old, things are looking significantly different for James than anyone else in NBA history: taking all of the above factors into account, he is still averaging 23.5 points, 7.9 rebounds, and 9.0 assists this season , which is an all-star performance in virtually every way. And while he may not be ready to play “until the wheels fall off,” LeBron James is taking NBA fans with him at every moment as he rides off into the sunset.