How does the interpreter determine whether a lexical is no longer "used"? You have to explicitly set it to undef? That seems doesn't seem like too much a "feature". So my memory usage won't really top out until all my functions have been called and all my variables used, is that correct?

I didn't know that about AUTOLOAD(). What do you mean by 'allocate additional memory every time'? Does that mean that every time I effectively call AUTOLOAD() (In my case, once for each undeclared function as I use AUTOLOAD() to then declare the function), the interpreter allocates a chunk of memory, or just that everytime I load a module with an AUTOLOAD() in it, it will allocate a larger chunk of memory than it would for a regular module? I know I miss out on compile-time optimizations for the system, but do those optimizations involve the re-use of resources, as opposed to the allocation of resources (which I know they involve)? I would expect that resource re-use would be a function of the running system, not the compile-time optimizations. If perl allocates memory for eval'd statements and AUTOLOAD()ed subroutines and then doesn't re-use it, that sounds like a pretty serious issue.