Donald Knuth on optimization

Apropos to the debate on perfection vs imperfection:

Programmers waste enormous amounts of time thinking about, or worrying about, the speed of non-critical parts of their programs, and these attempts at efficiency actually have a strong negative impact when debugging and maintenance are considered. We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil.

Donald Knuth quoted in Ken Kocienda’s Creative Selection