We're just about finished rewiring our 3+ story 1911 home (no ungrounded circuits now). Our insurance company informed us that without a rewire they would no longer insure. When I bought it had a mix of mostly two-wire knob-and-tube with some grounded circuits, but all had modern three-pin plugs. The previous owner had introduced some GFI plugs in an attempt to pretend the circuits were grounded but... We now have a 200 amp main panel, a 100 amp that handles the second and third floors and another 60 amp panel in the garage. A lot of work, but only cost about $3,000 or so in the end. One gets very devious at fishing wires after a while. This is the second old house rewire. The first was owned by an old electrician and had cloth lamp cord running to some of the outlets that were in the floor.