I mostly let my Pokémon only with Physical moves.
I don't know, I like to keep on causing damage.
You mean moves like Surf with Special moves? If so, all the time. I don't like Physical moves because of Pikachus and Shroomish etc. that can give you a stupid Poison and Paralyze
I like to have at least one Pokémon on my team who can lower the foe's stats and use some Leech Seed and Poison Powder