Given the complexity of the modern game, there’s plenty of things a player can pick up a fine for.
A post on social media, a comment to the press, or some ill-advised activity off the pitch are all likely to end up costing you a chunk of your wages if you’re a footballer.
And at Celtic, it seems talking to an international teammate in your native language in the dressing room is also on the naughty list.
Norway teammates Mohamed Elyounoussi and Kristoffer Ajer have found that out the hard way this season.
Elyounoussi joined Celtic on loan from Southampton this summer, making him the second Norwegian in the current squad and giving Ajer a compatriot for the first time since he joined the club in 2016.
It seems the pair have had to keep their conversations in Norwegian out of the Celtic dressing room, though, as a result of captain Scott Brown’s ruling.
“It’s always brilliant to get Norwegians up here and be able to speak some Norwegian,” Ajer told TV2.
“We get fines from Scott Brown for talking Norwegian in the Celtic dressing room, so that’s fine, that.
“There are fines every time we speak Norwegian. I’m good at chatting away, so it ends up with Moi (El Younoussi) having to pay a fine.”
“£100 every time you speak Norwegian. And if you come from Southampton and the Premier League, it’s £200.”
The pair certainly seem to have no problems with how Scott Brown runs his system for Celtic fines, even if it means El Younoussi having to cough up the money.