There's the bumper sticker philosophy that says, "Live every day like it was you last." Well, it seems to me that it overlooks the fact that if you were going to live like you were about to die, one of your main orders of business would be to notify your friends and family of the situation, and that's really going to open a can of worms. I don't think this experience would be liberating so much as it would just make for a very dramatic day. Everyone would be crooning around you, dumping attention on you and possibly granting you once-in-a-life-time wishes. This experience would no doubt inspire you to great emotional heights and depths, out of which presumably would come some kind of clarity about what's important in the world and in your final day. This is the crux of the philosophy- enlightened opportunism. If you are thinking about actually living every day like it was your last, rather than just putting the bumper sticker on you car, then this is worth considering.
Case in point, one of my favorite movie scenes of all time. It's in Wes Anderson's The Royal Tenenbaums, when Gene Hackman as Royal tries to persuade his ex-wife Angelica Houston as Ethel to let him move back into the house with her and the kids. Hoping to use her pity (rather than admit he's just out of money,) he tells her that he's dying. They're standing out on the sidewalk where Royal has sort of ambushed Ethel to have the big conversation. First he just asks her if he can spend some time with her and the kids and she pays him no mind, but as soon as he drops the D-bomb, she stops in her tracks and gives his request her full consideration. Then she begins to break down, sobbing and growing hysterical. Royal clearly didn't anticipate, or plan for the outburst, and looking to calm her down, tries to retracts his initial statement, telling her, "ok, now wait a second, I'm not dying." But then she becomes enraged, smacks him in the face, and begins to storm away. Again caught off guard, and realizing his first strategy was the only one that was going to succeed, he reverts to the initial claim, saying, "Ethel, baby, I am dying." Ethel gets up in his face, and asks with the fierce concern of a stern mother, "Are you or aren't you?" He sticks with his final answer, and alas it is settled that he's moving back into the house.