No manager walks into a new club and immediately knows what their best XI is.
There's a whole host of factors to consider - the majority of which can only be assessed from inside the club - such as how well individuals train, what sort of form they're in and what their attitude is like.
However, after nearly four months in the job you'd like to think you weren't far off. So why is Thomas Tuchel so insistent on tinkering with his starting XI?
Far be it for us to start picking apart the work of a man who's transformed Chelsea's season, taking them from ninth in the league to the top four - not to mention the small matter of reaching a Champions League final.
However, if the Blues fail to beat Manchester City in the showpiece event later this month they'll be relying on their league standing to secure their place in next season's edition of Europe's premier club competition, and fourth spot is far from rubber stamped.
Given their commitments in Europe over the past few months, Tuchel has of course looked to tinker with his starting XI to keep things fresh, though the seven changes made at home to Arsenal on Wednesday night just seemed utterly unnecessary.
Trying to add fresh legs to the side is one thing, but is there any need to rotate goalkeepers? Especially when one of said shot-stoppers is Kepa Arrizabalaga. It was almost as though Tuchel was trying to make a point - we're just unsure what.
Chelsea's first half performance looked completely disjointed, though you'd expect as much from a side with just four players remaining from their stellar win over the recently crowned Premier League champions at the weekend.
Were Tuchel's men ten points clear of fifth place with four games remaining it would have been kind of understandable, but the fact of the matter is their 1-0 defeat to Arsenal now leaves them just a point ahead of Liverpool should Jurgen Klopp's side win their two games in hand.
We're not going to overlook the fact Chelsea have an FA Cup final to look forward to this weekend, though you'd have to be pretty naive to be under the impression any Premier League manager would prioritise that over Champions League football - money is quite important to the big clubs, remember?
Tuchel's constant chopping and changing of his starting XI seems to have worked for him until now, though you have to think there'll be a tipping point for his players where they suddenly realise that no matter how well they play or who they beat it's just never going to be enough to cement their place in the side for the next outing.
A win for Chelsea against a subpar Arsenal side would have pretty much put to bed any doubts over whether they'll be featuring in next season's Champions League, though they now face the prospect of two nervy clashes with Leicester and Aston Villa.
Whether Tuchel's tinkering will come back to haunt him remains to be seen, but you can guarantee if it does he'll look back on his side's defeat to Arsenal as a huge missed opportunity that he probably could have prevented.