|Why do you only dig a small part of a site?||
It took several years to excavate the remains of this house.
|Excavation is very expensive and slow. It can take years of field seasons to excavate a small percentage of the whole site.
It's also important to leave things for future archaeologists to find who might have better techniques for finding and analyzing evidence than we have now. You want to give future archaeologists a chance to make new discoveries.