One downside is that you are assigned on-call shifts about once every 2-3 months and there is no built-in recovery time earned from this. However, most Supervisors allow you to start late the next day if you were out late for an on-call shift. You also have the option to give up your on-call shift to someone else, but it is ultimately your responsibility if no one wants to cover it (usually someone does). Personally, on-call was a great way to make extra money quickly and it also significantly expanded my knowledge base and skill set from interacting with different professionals during the shifts (i.e. doctors, NPs, nurses, crisis intervention, etc).