Oh, as many as you want. 

Let's say you are a Warrior Monk. You don't need

Intellect (magic healing sat)
Willpower (magic damage)

Because you use no magic attacks. You would be pure physical. The same if you were purely magical. You wouldn't need strength. So spend your points wisely and try not to waste them. Take a look at my character in the character section for an example. He's not finished yet obviously but his points are done.