Choice of Lewis Acid for EAS reaction Why is AlCl3 or FeCl3 might be preferred for chlorination reactions and AlBr3 or FeBr3 for bromination reactions? Why not use AlCl3 for bromination reactions?

Source: https://www.masterorganicchemistry.com/2011/07/22/reagent-friday-aluminum-chloride-alcl3/
Honestly speaking I think there won't be a difference as in clayden they have used $\ce{AlCl3}$ for bromination


If I had to give a reason it would be that when the $\ce{ AlCl3-Br2}$ complex is made there might be a teeny tiny chance that instead of bromine breaking away the chlorine  breaks away. 



My basis of saying that the probability of chlorine breaking away is low is because there's a +tive charge on $\ce{Br}$ in the complex.Chlorine on the other hand is free from any such effects. There are no factors supporting the breakage of the $\ce{Al-Cl}$ bond. So the chances of $\ce{Br-Br}$ bond breaking are higher than the $\ce{Al-Cl}$ bond. 

The same reasoning can be applied for $\ce{AlBr3}$ with $\ce{Cl2}$

That's why in Master Organic they've written preferred not necessary.