I have a practice routine that I do 2, 3 and 4 notes per string to a metromone. I was thinking about cutting out the 4 notes per string exercise because nothing ever requires 4 notes per string. Is that a good idea?
Earth without ART, is just Eh...
nothing requires four notes a string?

Do you practice your reading? Instead of practicing how many notes per string you're playing try practicing exercises out of a book. Open a book to a random page and try to play it.

Your sight reading skills will improve and you'll get much better.
Why leave it out? The experience from playing four notes a string directly translates to more precise fretting, no matter how many notes you play per string. It helps getting used to using all of your fretting hand's fingers too, many guitarists don't do so and therefore limit themselves technically. Some just don't use their pinky enough, for example. That's stuff you won't have to worry about if you keep up your good practice routine.
SenorSmiley - yes, I am well aware of that. that's not what I was asking either and doesn't relate to my question.
Earth without ART, is just Eh...