Putting code into a module doesn't have any real impact on how much memory/CPU it uses.

I have a couple special scripts that I use quite a bit. I include them as needed

What you do mean when you say that you "include" a "script"? Not that I think knowing the answers to these questions will lead to revelations about big efficiency differences. And worrying about efficiency before you've noticed a real problem with lack of efficiency is usually wasted effort (or worse).

                - tye