Getting emg of legs next week. had emg 8 weeks ago. how often should they be performed?

Not sure why this is: Being done in such a brief interval, but there may be good reasons if you are encountering acute changes. My colleagues do not routinely repeat studies in stable patients unless the first test was incomplete or done inappropriately.

Not typical: It depends on the problem and the acuteness. Unless you are actively monitoring a condition that has the potential for change (e.g. Guillain barre syndrome) or if there was some kind of dramatic change, it is unclear why a repeat EMG is done at this unusually brief interval.