Perl's memory should flat-line ... if you programmed it right. Some things to check:

1. Are you continuously adding elements to a hash or array? For example, if you keep doing something like $foo[$i++] = $bar;, you keep telling Perl to increase the size of @foo.
2. Do you have any circular references? They are a cause of true memory leaks.
3. Are you scoping things as much as possible? Do you have any large global hashes/arrays that you could scope a little smaller?
4. Are you constantly loading new classes/modules? I was on a project for a OO application that would dynamically load the classes it needed as it needed to. Every time that happened, the memory usage would increase, but only a fixed amount.
5. Are you fooling around with deleting from %INC and @INC? I'm not sure what that would do, but it probably won't actually remove the initial require from RAM.

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/me wants to be the brightest bulb in the chandelier!

Vote paco for President!