I do have office hours (and kick myself sometimes because of it LOL) but they're Monday - Thursday 10am - 5pm Eastern, Fridays by appointment only -- they're usually my admin and marketing catch up day or just my "getting-together-with-my-friends-for-long-lunches days".
I have a welcome package that I send to my new clients which states my office hours and policies (i.e., we will only accept task requests by email). I also let them know that if I'm absorbed in a project I don't answer the phone.
I personally love the idea of NEVER answering my phone again

Some days I seem to be on it from the time I wake up until late in the afternoon.
Interesting to read all your policies and thoughts on the subject!
Cheers,
Pam