We should be aiming to automate all our testing

You've heard it.  I've heard it.  This is my response:

Don't (explicitly) charge your clients for testing

Software development houses who write bespoke software will usually provide a quote to develop or customise an application.  Often, it's broken down into "Project management, requirements gathering, development, testing/QA, etc etc".  In my experience, it is a mistake to break testing off as a separate quote to give to clients.

Why?