"Very fast. Let me explain.
"I work in 2 modes: (A) At the computer and (B) Away from the computer.
"When I'm in Mode A at the computer, I'm cranking out lines of code, testing, revising, testing, revising, etc. This process must be very fast. Several hundred lines of code (or whatever) in less than an hour. A complete cycle in less than a couple of hours. My guideline is that if I'm not working that fast, then I must not be prepared to work that fast, so I don't deserve to be at the computer. I should be in mode (B).
"Mode B is generally much slower. Reviewing code, specs, or notes. Refactoring code. Laying things out with pen and paper. When I have enough work clearly laid out, I know it's time to get back to the computer and return to Mode A."