After a while you will playing a large range of exercises. Using a Metronome When practicing exercises, it is best to use a metronome. Practicing with a metronome helps to build your internal clock so that when you play without one, you can keep a good lock on the tempo of the song without drifting faster or slower. In some cases this is a desired effect. However, in many cases it only detracts from the song making it sound out of sync with all the musicians.
Timing is very important for the drummer and bass player.
Guitar players and other instruments can many times get away with it, however, not usually the bass and almost never the drums. The other reason to play with a metronome is when you practice scales, exercises or new licks, it is much more effective to play slower at first and speed up only when you have mastered the lick at the slower speed. Using a metronome forces you to stay slow and not cheat and speed up in the middle of the lick. Your fine motor skills develop faster when you play slow. All you are trying to do is to teach your finger muscles what to do.