Thanks. I did try to coerce my customers away from phone support (by reducing my hours that I would respond to calls) and try to get them to use a ticketing system (Zendesk)). That worked to a certain extent, but still didn't fully eliminate those that were already used to phone support.

A ticketing system also helped with another big bugbear of mine - getting back to customers with long support ticket cycles, i.e. where I had to make bug fixes, test and deploy. I was frequently forgetting to get back to them to advise them I had fixed an issue. The ticketing system helped me to keep track of that.

Following up with customers was another mind loop that detracted from the freedom of mind I needed to develop good code.

At my last gig we had three support channels: phone, skype and ticketing. Standard workflow (which clients always tried to circumvent) was: client writes to skype/calls, we decide whether complaint is solved by a quick explanation and respond with a call, or problem requires more investigation/work and client is directed to submit a ticket.