Eddie Howe is about to find out that keeping 52,000 Newcastle fans happy every week is a very different kettle of fish from Bournemouth.
And I am not convinced that he will be able to save them from relegation.
Howe takes charge of his first game at St James' Park with just five points from 11 games on the board. The odds on clubs staying up after such a poor start are rarely favourable.
Yes, Newcastle are the richest club in the world now, and they can afford to buy anyone they want in January.
But by the time the New Year transfer window opens, another nine games will have elapsed and we will be into the second half of the season.
Of course, there is still plenty of time - more than enough - for Howe to collect the 33 or maybe 35 additional points needed to stay up.
And if he chalks up two or three wins early in his reign, the momentum should be enough to lift Newcastle safely into mid-table.
I always enjoyed watching Howe's Bournemouth teams, the way they made fast starts and their high tempo.
But in their five seasons in the top flight under Howe, the Cherries conceded 67, 67, 61, 70 and 65 goals. For all their attacking flair, they were not famous for keeping the back door locked - and Newcastle have yet to keep a clean sheet this season.
Will Eddie Howe keep Newcastle up this season? Comment below
And for all the good players he brought to the south coast - including Callum Wilson, Ryan Fraser and Matt Ritchie, who are reunited with him on Tyneside now - Howe's record in the transfer market was not faultless.
Yes, he sold Nathan Ake, Aaron Ramsdale and Wilson for a combined £78 million, which is terrific income for a club with an 11,000-capacity stadium.
But his most expensive buys - Jefferson Lerma, Dominic Solanke, Jordon Ibe, Philip Billing and Ake - about £95m combined.... were they all a success in the Premier League?
At a club like Bournemouth, when you spend big it has to be good business. And although he will have untold riches at his disposal, he will have to spend wisely at Newcastle.
Howe was under only limited pressure at the Vitality Stadium because nobody expected them to make it to the Premier League in the first place, let alone stay there for five years. No arguments, what he achieved there was almost a miracle.
However, the expectations at Newcastle United are miles bigger. They have the resources to strengthen their squad significantly in January, and Howe will be under massive scrutiny when he starts spending the Saudi owners' fortune.
Good luck, Eddie. If you start well, the Geordies will take you to their hearts and it will be a fantastic ride.
But five points from 11 games is such a poor basis for salvation that I still fear Newcastle might be going down.