kakashis drains fast cos he can;t control it, he cannot put it away like sasuke and his brother. the fact is it still drains fast but they have more control over it, the more control the less chakra it uses while active depending on what its been used for.Originally posted by: Kale Ironfist
thing is, the answer is already given in the manga/anime. why else is the Uchiha clan known as the number one clan in Konoha? The Hyuuga are only the number one clan now because the Uchiha got slaughtered by one man... an Uchiha himself...
Shi_No_Shikaku: the sharingan doesnt drain very fast... only on non Uchiha clan members...