again, on easier games it doesn't really matter, on harder ones (Conquest, RD, New Mystery, Berwick and only for me 3H) you should really calculate everything while on battle preps
If you want to plan well, you need to calculate everything before you even see the combat menu
atleast that's how i play FE. The harder ones anyway. Easier ones is just sending someone to 20 v 1
Alm x Celica is really really bad. Not only do they have as much lines together as Sigurd and Deidre, there's also the fact that both Alm and Celica has much better Chemistry with other people than with each other.