People always ask "Will you have to cut a big hole in the wall to do that?" Today we had to add a few new outlets in a 1911 condo in Hyde Park. Here is one picture. Typically, we only have to make small cuts/notches in the plaster wall to
fish the BX or greenfield in the wall. We cut the lathe, which lays on top of the 2x4 framing, and then have to make a hole at every point where the wiring has to "pass" a vertical stud in the wall. Easy, peasy, Macaroni and cheesy!
One caveat, however. This only applies to interior walls. If the wall is an exterior wall, with brick on the outside, it is an entirely different matter. In that case, there is rarely (like never) framed with a 2x4. There is a 1" (if that) furring strip nailed to the inside surface of the brick, and the lathe is nailed to that. The cavity is much more shallow. There is also, generally speaking, 80 years of dirt, dust and all manner of debris piled up in the wall, as well as hardened plaster that was generously slathered on by somebody's lone past great grandfather.