As a prince and as a future king, William has worn and will wear plenty of uniforms.
But the flight suit he'll hang up after his last shift has particular significance.
For two years it's been his "passport" to a life where, on merit, he helped people save lives.
This after all is a man who wishes that when he was younger he could have done more to protect his mother.
He's been exposed to the National Health Service in a way that no other senior royal has been or possibly ever will be.
It's an experience he's determined will shape his future.
The words the East Anglian Air Ambulance use to describe the pilot prince are warm, not perfunctory.
They're losing someone they call "much loved", "hard-working" and a "wonderful character".
William is losing something he's cherished - working in a team.
A lonelier destiny, which he's put on hold for so long, now beckons.