One of Floyd Mayweather's retirements lasted two months. Lleyton Hewitt changed his mind after a month and returned to the world of tennis having spent nearly a year saying goodbye. Sugar Ray Leonard took just a week to U-turn on his big decision to quit boxing. Conor McGregor lasted two days before he was back in the fold and raising hell in the Ultimate Fighting Championship.
By comparison, Scott Brown has had a long and happy retirement from Scotland duty - two-and-a-half months. He's back now, though. What we don't know is for how long he is back.
Confusion reigns on that one. Mark McGhee, Scotland's assistant coach, kicked it all off last week when he said that Brown was coming back and that it was 100% Brown's decision to reverse the call he made in August.
Back then, the player spoke about his inability to give everything to his club and his country without letting his standards drop.
There would have been a physical dimension to this. Brown struggled with a knee injury for much of last season. "I simply felt that I could not keep up both commitments [club and country] without either my performances or recovery time suffering," said the Celtic captain at the time.
McGhee spoke about Brown "revising his decision" because he felt he had "more to give".
This was a cause for celebration. Having ended last season a diminished character, Brown has been excellent for Celtic this season, his power and influence restored, his fitness good, his hunger insatiable, his leadership strong. He's played some of his very best stuff since Brendan Rodgers became his manager at Celtic Park.
Scotland's World Cup campaign suffered monstrous damage with the home draw against Lithuania and the wounding loss away to Slovakia, but when the news broke that the country's best player was on his way back it offered a little succour in grim times.
Then, along came his manager at Celtic, Rodgers, to throw a bucket of cold water over the notion that Brown was back to stay. "He's made himself available for this game," said Rodgers. "I think it's just for this game."
He should know, right?
So, one-and-done? Wembley and out? A farewell rather than a new beginning?
That's not the message that McGhee was putting out last week. Scotland coach Gordon Strachan had an opportunity to clarify all of this on Wednesday, but he didn't take it.
Is Brown back for the long haul? Well, they'll review it after Wembley. Does his commitment extend beyond a single high profile match? Mibbes aye, mibbes naw.
Mibbes it would have helped if this decision was made before the last round of qualifiers, when Scotland desperately needed some results - and didn't get them. Sure, Brown wasn't ready to jump at that point and that's understandable. It's a major pity, though. The damage has now been done.
Unless a famous victory is won at Wembley, Brown's sudden appearance is going to look a bit like a man busting in on a funeral with a defibrillator.
Scotland will be a better team at Wembley with Brown in it and that's all that Strachan cares about right now. The idea that a player can pick and choose which games he wants to play in may stick in the craw of some Scotland fans, but Strachan won't bother about that.
After all, it's not just Brown's future that is up for grabs against England, it's Strachan's, too. In that light, it's tempting to see the Celtic man as Strachan's 'break glass in case of emergency' option.
For one thing is indisputable. Scotland have now reached the point of crisis in their World Cup campaign. Cometh the man, cometh who knows what...