I had one done - took a couple of sessions. A great dentist and it didn't hurt a bit. He even phoned me up a few hours later to see how I was doing and I could happily let him know that it was all fine.

I have been advised by another dentist though recently that I will need a crown on the root canal tooth to save what I have left to protect it for another 15 years or more. She said it should be done within 5 years (max) of the root canal treatment.