I'm in the process – have been for a year or so now, I guess – of extending/expanding my "scholarly base," of stretching out from being a modernist/20th-century person to having more than a nodding familiarity with Victorian literature & culture. This year alone I've probably read about 30 books this year in the field, bunches of articles, etc. I've done a couple of related conference papers now; I wrote a review of a new Ruskin book a few months ago.
So when do I start actually writing this big book? My own inclination is to keep reading until I know enough to do it right, but there's always something more to read. I suspect that if I wait until I feel totally ready to tackle the next thing, that I'll die of old age before I ever put fingers to keyboard.