The operative word is "premature". Optimize when it is time to optimize - the OP touches on that. If you know a given routine will be run a lot, then some opti

The operative word is "premature". Optimize when it is time to optimize - the OP touches on that. If you know a given routine will be run a lot, then some optimization right off the bat is a good idea. Now, that "knowing" is a little more difficult, but comes with user feedback and experience.