I've had three root canals. One became infected while the temporary cap was in place and waiting on the crown. I left on a 4 day trip to dark country for astronomy the day after the root canal and spent the time in wonderful pain. For another root canal, I arrived in the morning and the receptionist told me I'd have to reschedule as the compressor that runs all the air tools had malfunctioned and they were having to cancel and reschedule all appointments. I offered to take a look at it, got it running in a couple minutes. After the procedure I came back to the receptionist to cover my copay portion....the dentist walked over and said, "Are you kidding? If you hadn't fixed that we'd have had a scheduling nightmare and lost an entire day's work! You don't owe anything."