So, when I worked as a set PA on the West Wing (7th season), we were filming a scene in which the President storms into the Situation Room to be briefed on possible invasion plans regarding a former Soviet republic. The President chews out the general, Fitzwallace about "what jackets" the troops would be wearing during the winter invasion. At the end of the scene, the President storms out again in a fury. Since it was a moving dolly shot within the room, it was my job to cue the President when to walk in through the closed doors (cue originating from the 1st AD by the monitors).
As we waited, Martin Sheen looked me over and said, "How old are you John?". I replied, "23".
"My God"... Martin laughed and looked up towards the heavens. "23. My God... 23. You must be the youngest person here!" (I actually wasn't). The secret service agents behind him chuckled. Martin then fiddled with his cane. "If I knew I was going to live this long, I would have taken better care of myself!". He and his "agents" shared another laugh.
I got the notification over the radio, "Rolling". I relayed to Martin "Rolling". He composed himself, dusting his suit sleeves and flexing his cane. He then got into character, staring ahead of him.
The President then turned to me, squinting his eyes and half pointing his cane. "Take care of yourself, you never know how long you'll live". President Bartlet finished the line with his trademark roll of the head and nod. I nodded back.
"ACTION!". The President stared at me for his cue. Over the radio: "Martin". I then waved the President in, and the scene played out.
So, as someone that has technically served at the "pleasure of the President", all I can say is please take care of yourself, you never know how long you'll live. This is coming from the fictional President of the United States, a very sweet person, and the father of Charlie Sheen. That should mean something.