Japhy is correct. To add on. Don't plan your design around speed unless you are doing some rather heavy stuff. Most of the time your scripts are to simply automate and spending time worring about shaving off a few ticks here and there really doesn't get you much. Especially when you consider that perl is mainly interpreted.

I used to think the same way till I think it was Abigail-II who gave me a smack upside my head and told me not to waste my time. ;-)

Also, agree with the "use benchmark" suggestion!