I recently contacted an electrician to help provide a quote for a possible knob and tube rewiring job. Contractor came and saw and based on what he saw, it was better to start my insulation work and call him if knob and tube shows up (he didn't think I had any in external walls).

Later, I was charged a $300 service call fee for the visit. No one mentioned the visit would cost money. If it did, they should have mentioned it when I booked them. Is this common or fair?

I understand these visits take time, but I would have appreciated knowing upfront so I wouldn't have had this contractor come then.