Which have you found more beneficial: playing through a large number of games quickly, or studying a smaller number of games, but in more depth? Have you played through all of the analysis of an extremely deeply annotated game (like you find in Kasparov's books), and how beneficial did you find it?
Always one game.
In my ultra keen days. (I refer to them as my chess and cornflakes days when
I would eat my breakfast whist looking at games of chess or positions and
that would be the theme for the whole day.)
I would put games through a mind mangle squeezing out everything and
often being left with a whole batch of unanswered questions that needed
further study.
Great days. Often I would analyse myself into a deep whole and have to start
all over again.
In them days no computers so you had the added bonus of perhaps finding a
quicker win or an outright blunder in the notes.
It was not all that uncommon to find a 'hole'. It's where the saying:
"If it's long [analysis] then it's wrong." came from.
If you found something you either kept it to yourself if it was in an opening
book or fired off a letter to CHESS or BCM.
Mr Thomas mentioned in Fischer's 60 was such a letter where he found a
move that Fischer had missed that would have forced immediate resignation.
The whole history behind this note and some more Fischer 'Mysteries' can be found here.
http://www.chesshistory.com/winter/extra/fischer1.html
I recall Tony Miles spotting a blunder in one of Levy's books on the Dragon,
using it and winning a game.
Also in the first book on the Benko there was a glaring hole. (see below)
These days a computer has run over everything and you will not find any
juicy errors.
For me I don't have time devoted to chess study so it is a bit spontaneous, openings tactics, playing games etc. I like logging on to the chess servers, playing through live GM games and seeing if I can follow the logic.
E.g game I was taking a peek at will look at the end of the day to see what happens
Conclusion of above game I was surprised at white's opening choices and look what happened.