The most obvious case would be the replacement of a single global variable with a scope-restricted variable and access methods for it. IMHO, this would be an improvement even if the code that uses those access methods needs additional temporary vars to work with it.

   {   # scope of foo_tracker
      my $foo_count;

      sub found_a_foo()  { ++$foo_count; }

      sub foo_count()    { $foo_count; }

      sub killed_a_foo() { --$foo_count; }
   }   # scope of foo_cache
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That said, I do favor refactoring code to reduce the number of variables passed into a function, or the number of levels through which an argument is passed before it gets used.