the idea of the 1234 chromatic excercise is great but surely boring. you can get creative with it and add other things like different picking techniques to it.
examples: all down, all up or
alternate picking. i think it is a good idea to have a metronome to play along with and also adding the open string as well - especially with alternate picking. if you play 01234 with alternate picking going up every string from low to high and then from high to low without missing a beat, you will alternate the first picking of each string between up and down strokes. being groups of 5 notes per string it just naurally works that way and is a great way of breaking the monotony of playing squares.
i call the 01234 excercise the caterpillar - i didn't name it but that is the name i've heard alot. Vai has a cool version where you play diagonally across the strings instead of going up and down each string. that is a great one to build strength, control, stamina and help with dexterity.
scales are also great to apply the mechanical side of playing but do add the musical side of playing. you can get really creative with how you play them. for example, take a mode and learn all the notes of that mode all the way up two strings to either the 12th or 24th fret and practice going up and down it in creative ways,ie: alternating open strings different groupings of notes creating different rhtymic and melodic sequences. again, play along with a metronome and try subdividing beats around to keep boredom from setting in. you always want to watch your technique when practicing exercises so you don't incorporate bad habits into your playing. it takes less time to apply good technique habits than to break bad ones.
