I'm flying HEMS now and the days are getting longer and the calls fewer...
When the calls get few enough, the base may close, so it's extremely important to know when to accept a call and when to turn it down. Study the NTSB record of all HEMS accidents for clues on how to avoid being put on that list. Jot down interesting lessons learned and share them at safety meetings with the other pilots. Before long, you will be the base safety officer and will have lots less time on your hands. Then when a base manager slot opens up, you can move right in and make a better salary. (Unless you're working for Air Methods).