in reply to Use strict warnings and diagnostics or die

One little thingie ... use diagnostics; slows down the execution. Therefore I'd recomend using it only during development and only if you do not understand some warning or error message. Besides ... you can always find the longer explanations in perldoc perldiag.

use strict; and use warnings; on the other hand can never be overrecomended (hope there is such a word in English).