Nowdays, it seems to be standard for jewish family's to begin cleaning their houses days before Pesach. By the time bedikat hametz arrives, the houses are usually hametz free.
From reading Talmud Pesachim and Rambam, it seems that Chazal envisioned all the cleaning to be done the night of bedika, and weren't so meticulously with all the tiny specs of hametz as we are nowdays.
1) Is what I'm saying true? 2) if not, why didn't Hazal tell us to make the bracha for bedikat hametz when we started cleaning days/weeks earlier? Why wait for the houses to be hametz free the night of eruv Pesach?