If I could do it over, I'd read O'Brian's novels with several months to a year between each one (perhaps one every winter and summer solstice). There's really something to be said about savoring such an authentically detailed, nuanced, and intellectual universe.
As it is, I find my recollections of the Aubrey-Maturin adventures muddled and vague, since I burned through the first 20 at an addict's pace. Not recommended.
They keep going with the same level of quality until the very end. Even the three draft chapters of the unfinished 21st volume left me wanting more.
Agreed. I read them as slowly as I could manage over the course of about five years. Even 21 was a great read. I was blown away that I was still maintaining the same enjoyment 15, 16 books in. I just assumed the quality would have had to deteriorate. Although O'Brian does get a lot of reuse out of Stephen's joke about the dog watch being cur-tailed.
I wish I still had eight and a half more to go!
Math is slow because you have to work things out as you read it.
Books written very long ago are slow because I read them like a detective, looking not just at what the author means to say, but also at what he's saying implicitly about how things were at the time.
Other books I read slowly because they're so good I don't want them to end. I used to have to make a conscious effort to make Patrick O'Brian novels last, and I stopped reading them at about number 12, to save the rest for later. (I worry though that I wouldn't like them so much now.)