I've been a "code starer" for 30 years and emphatically wouldn't do it differently. I want the model of the program in my head to be so faithful that I can, and

I've been a "code starer" for 30 years and emphatically wouldn't do it differently. I want the model of the program in my head to be so faithful that I can, and do, spot bugs by 'running' it there. I'll happily stare at code until that's the case. That state of things maximizes the speed I can work at relative to the stability of what I write. It's not at all uncommon for me to write code for weeks without even compiling once. And usually when I finally do compile and run, there is very, very little to debug. This approach also answers (to my own satisfaction, if nobody else's) the old question "how can you refactor confidently without unit tests?" Because I can prove the equivalence of any refactoring in my head, the exact same way I can recheck an algebra problem and known it's right. To me, code is a math problem. I don't mean the arithmetic in the expressions. I mean the whole structure of the program is one big math problem.