Mythical man month: 10 lines per developer day
What annoys me most about these metrics is that some days zero lines are written. Anything up to a month without results to show.<p>Where, then, does all this time go? Sometimes it's reading existing code. Sometimes it's learning about a new algorithm by reading blogs and papers. Sometimes it's developing test programs to iron out a bug or test out some new code.<p>There used to be one chap in the office that got all the hard problems - the seriously hard problems. Some of this was figuring out why USB couldn't transition from low-speed mode to high-speed mode reliably (USB is quite hard to probe due to frequency), or figuring out why the application crashed one in a million boots.<p>Some of our most valuable developers committed the least amount of code, but saved our arses more times than I can count.