I once described this novel, to a student, as being not about happy or sad endings, but about what was left of the characters when it was over. "No Country For Old Men" definitely has a tone of disillusionment and fatalism that give rise to many examples of loss and survival in a semi-cyclical relationship.
Spiritual Loss/Loss of Faith: Bell says at one point,
I always thought when I got older that God would sort of come into my life in some way. He didnt.
Bell hasn't exactly lost anything (since he's implying God wasn't in his life, so he had nothing to lose) but this is more of a sense of disappointment; Bell was probably looking forward to peace and guidance that never came.
Bell's decision to retire can also be seen as a loss of faith in both himself, and the role of law enforcement.
These old people I talk to, if you could of told em that there would be people on the streets of our Texas towns with green hair and bones in their noses speakin a language they couldnt even understand, well, they just flat out wouldnt of believed you. But what if you'd of told em it was their own grandchildren?
This quote comes amid a passage speaking of disillusionment and a change in times. The point is that America is becoming unrecognizable to Bell and those like him.
Financial Loss: Loss of money is the reason for Chigurh's entrance into the story, and in the final paragraph, Bell mentions dreaming of having lost money that his father gave him. Money is most likely a MacGuffin which represents responsibility, success, dreams, etc.
Loss of Life: Death appears frequently in the story, and can be thought of as an ultimate loss. Death is one of, if not the primary, consideration for Bell when he decides not to pursue Chigurh when it becomes clear that this will be likely to end with his own death and Chigurh's escape.
Loss of Control Over One's Fate: Chigurh is sometimes depicted as a ghost, and the death that he brings as a force of nature. His conversation with Carla Jean emphasizes his own inability, as well as Carla Jean's, to alter the course of fate; everything is proceeding as it "must".
Everthing I ever thought has turned out different, she said. There aint the least part of my lifeI could of guessed. Not this, not none of it.
An aged man is but a paltry thing,
A tattered coat upon a stick