An American president is said to be at his most powerful in the first hundred days of his presidency.
Get it wrong in those opening few weeks and he - so far it's always been he - is unlikely to ever be trusted to get it right.
It happens though. And many minds will have been made up about David Moyes as Manchester United manager even before he passed one hundred days in charge last week.
The international break might have allowed Moyes a period of reflection last week.
United got through another test at Sunderland, perhaps uncovering a new star in the process.
That brought down the curtain on a couple of months where iffy form segued with an apparently cack-handed approach to the transfer window.
Replacing Sir Alex Ferguson was never going to be easy.
When United appointed Ferguson all those years ago they thought they'd finally found the heir to Matt Busby, Bill Shankly and Jock Stein.
When they appointed Moyes this summer they hoped they'd found the heir to the heir.
It took Ferguson time to find his feet. Moyes won't have that luxury.
Not only has the game moved on and the fevered press grown worse but Moyes inherited champions. His job was to build on success not to rip everything up and rebuild from scratch.
That's perhaps a bit unfair. Ferguson's final championship wasn't delivered by his finest side. While he didn't sell Moyes a stuttering jalopy, he did leave a motor that needed some attention.
Moyes has quickly discovered that patching up a second hand football team isn't as easy as identifying what spare parts you need and visiting onlinecarparts.co.uk to get the problem car sorted.
This first post-Ferguson summer made the release of David Peace's Red or Dead, a fictionalised account of Bill Shankly's reign at Liverpool and his apparently melancholic retirement, seem even more timely.
(It's certainly written in a unique style but I felt that was essential for building the "Shankly" Peace wanted to create. For those of us who know Shankly only through the soundbites, the achievements and the second hand memories that fictional version seems somehow real. My own view is that the book is a triumph. And here endeth the sub-Higher English literary criticism.)
By calling it quits and then talking about how he's embracing retirement and leaving the new man to it at Old Trafford, Ferguson's desire to avoid the various fates of Stein, Busby and Shankly seems almost too conspicuous at times.
Shankly left Liverpool to a reluctant but incredibly successful Bob Paisley. Busby left Manchester United to a succession of men who couldn't match him until Ferguson - and a patient board - came along to get it right.
100 days of David Moyes isn't enough time to decide whether United have made a huge mistake this time.
He could argue that he's six points off the top of the league, undefeated in the Champions League and enjoying the performances of a restored Wayne Rooney.
All true. None of it enough.
He can't do anything about the transfer window right now but he needs to follow the international break with a sustained run of wins.
Getting Adnan Januzaj tied to a longer deal would also be a sound move - as a player he offers only potential but his capture would at least be a signal of intent.
Above all - and this will only come with wins - he needs to move the story on from his ability to do the job.
In the past couple of weeks I've read Moyes defending himself, Ryan Giggs defending him, Alex Ferguson defending him, Dion Dublin defending him and Luis Saha defending him.
That's an awful lot of David Moyes. And I'm not sure continually protesting that someone is the right man for the job is the best way to convince people that someone actually is the right man for the job.
It could be, after a successful few seasons, that we look back on Moyes' first hundred days as the weakest period of his reign.
That would be understandable. The pressure of replacing Ferguson, a new chief executive further complicating the transfer window, players adjusting to the day after the knight.
But Moyes needs to recover - at least in the short term - with a team that so far hasn't looked strong enough to cope with the biggest challenges.
After 11 games in charge Moyes might reflect on a few things.
Firstly, he might ponder, the first 11 games are hardly enough of a window in which to draw conclusions about a manager.
Secondly, he might worry, the first 11 games have undoubtedly made his dream job even tougher than he might have imagined.
Thirdly, he could think, the first 11 games better not be fodder for another David Peace book. Because nobody wants to provide the sequel for the Damned United.