with me, i dont have a "MUST PRACTICE" rule, but out of both curiosity and creativity and enjoyment i pick it up and play, several hours a day. im no speed king, although it would be nice, im content where im at.
Im no song king either, im what you would call the anti-synth drone, i make my own stuff up, i have probably 2 sets worth of songs made (most arent completed yet...like i need to get lyrics, or start writing lyrics soon...)
but hey, creativity is king in the land of Guitar, and there ARE people who are without it.
edit-
*** i do know my theory though, so its not like i just make up crap that i dont know whats goin on***