I changed my service (100A zinsco to 100A QO) and I only did AFCI for bedrooms and the living room. I'm not really worried about romex as I am a table lamp, which the cord might get caught under a chair leg or something. I do have 3 knob and tube light circuits, but generally there's less chance of an arc because the wires are almost stud length apart (except at the terminations because of degraded insulation.)
My AHJ is pretty good on the AFCI. For example, it is city code that for any abandoned (as in taxes not paid) building, in order to be resold, must have all new wiring, gas, and plumbing. They MUST have AFCI in the bedroom, and the city was offering a tax break on up to 2 additional OPTIONAL AFCI's. Our inspector is pretty uptight, but with good reason, especially since the houses are so close together. (I'm not 100% sure if it city code not to granfather, or if it per contract, but the city treats it just the same)
