See also A better non-existant string... where I note:

This means that if your script has four thousand 3200-byte strings enclosed in double quotes, then you could make it start up 0.2 seconds faster by changing all of those double quotes to single quotes. No matter how long the script ran, no further speed benefit would be achieved.

which means that worrying about such things wastes more time than it saves for most people. (:

        - tye (but my friends call me "Tye")