Count if at all possible. Compute when you can’t count. Use judgment alone only as last resort. (Steve McConnell)
Count-first is the approach that Steve McConnell suggests in his Software Estimation book.
If you can count the answer directly you should that. […]
If you can’t count the answer directly, you should count something else and then compute the answer by using some sort of calibration data.
Reading about this approach makes me think about how I estimated things in the past. My job is changing and the tasks of estimating and scheduling are more frequent. I know that software estimation is hard and crucial for every project to succeed.
If you, like me, are having troubles on software estimation I strongly recommend Steve McConnell’s books “Software Project Survival Guide” and “Software Estimation”. They are like strong related cousins; you’ll be a better software project manager if you know how to estimate and you’ll estimate better if you know how a software project has to be done.