In TMWTGG, we can see developing something strange in Bond's world : nostalgia.
The first hints took place at the beginning of OHMSS, when Bond, on holidays, is daydreaming about his childhood on the beach in Royale-les-Eaux. Then, in YOLT, we can see him, depressed an drinking too much, more self-conscious of his failure and weakness, both physically and mentally :
The state of your health, the state of the weather, the wonders of nature - these are things that rarely occupy the average man's mind until he reaches the middle thirties. It is only on the threshold of middle-age that you don't take them all for granted, just part of an unremarkable background to more urgent, more interesting things.
Until this year, James Bond had been more or less oblivious to all of them. Apart from occasional hangovers, and the mending of physical damage that was merely, for him, the extension of a child falling down and cutting its knee, he had taken good health for granted. The weather? Just a question of whether or not he had to carry a raincoat or put the hood up on his Bentley Convertible. As for birds, bees and flowers, the wonders of nature, it only mattered whether or not they bit or stung, whether they smelled good or bad.
(from YOLT)
Starting from YOLT, Bond is ageing. He has to deal with past, with memories, with deliquescence. This is odd, because according to the filmography, Bond is a mythical hero, always in the present, always a "young man in his mid-thirties" (or rather mid-forties, in the movies).
Of course as pointed in the excellent article by Jacques Stewart, in TMWTGG we see a New Bond in a New World, but nostalgia hasn't been washed away. There's an incredibly sad line (to me) in this novel, when Bond is at Kingston's airport :
What were a couple of hours of heat and boredom in this island compared with memories of Beau Desert and Honeychile Wilder and his survival against the mad Dr. No? James Bond smiled to himself as the dusty pictures clicked across his brain. How long ago it all was! What had happened to her? She never wrote. The last he had heard, she had had two children by the Philadelphia doctor she had married.
Thinking about this bright Honeychile Rider as a "dusty picture" is sad enough, but my heart sank when I thought about her as an american doctor's wife. Can you imagine it ? From a golden and shiny embodiement of Mother Nature, wilderness and freedom under the Sun and Ocean, to a middle-upper-class housewife in the north of Noth America ?
And this "She never wrote" : as if Bond regretted it, as if he missed an old friend.
Oddly enough, Bond had a story before the beginning of the novels. He had had his lot of war experience, and a carreer in intelligence before "Casino Royale". But as far as I can remember, there are no allusions to his war memories, lost friends etc. in the novels. Nostalgia seems to appear with the last three ones, just like if, before ageing, Bond had just been like a boy playing a game called war.