I would say mental health in an outpatient office is the easiest to code and to bill. A psychologist will see one patient every hour, almost all of those will be the same CPT code, and the diagnosis code doesn't usually change. The mental health software I used, when you were on the patient record, you hit F3 to bill a visit, and it would replicate exactly the last visit (you could change details if necessary). If you were billing the same day as the visit, then the dates wouldn't need to be changed and then you just hit F10 to save. So go to the patient record, hit F3 then F10 and you have charged the visit. Done. Bam. That's it.