I won't work on anything live unless absolutely necessary.

If you do have to do, have two journeyman there only one working at a time, take turns.

Tag and lock out the circuit you are working on. Don't use masking tape use a physical lockout, preferably one with a padlock. I carry the Klein one in my truck. You would be surprised how many times somewill will attempt to energize the circuit while you are working on it. "hey my ac is out, oh here's the prblem it's shut off" no realizing you are on the roof working on it.