Joel Spolsky writes:
A ridiculously small portion of the energy it takes to make a commercial software product actually goes into the writing of lines of code. I would estimate that out of every 100 calories expended by the Fog Creek team:
25 calories are spent on customer service
55 calories are spent on debugging, beta testing, and minor tweaks
8 calories are spent on marketing, including the Fog Creek website
5 calories are spent reading college kids’ resumes and interviewing said college kids
5 calories are spent on code that never ships, such as the online demo and the online store
2 calories spent on actually writing new lines of code that ship to a customer.