a) get as much background as you can as fast as possible (allowing for pacing and international conventions on the limitation of infodumping)
b) hold as much of the background in reserve for as long as you can (allowing for international conventions on opacity and cruelty to readers)
or c) there's always something else?
I ask because I've noticed that I tend to lean closer to b) than a) on my first drafts, but I tend to be very close to a) after revision. I'm wondering if maybe I should be sticking more closely to b), on the grounds that the pacing is more important than keeping the reader fully informed and, plus, it's fun to keep secrets.
When you're reading, which approach do you prefer?