I can only cache for about an hour to keep things fresh however. So I have to do a fair amount of work to accomplish that ...

Cache::Cache can help you here.

my $cache = new Cache::FileCache( );
my $result = $cache->get( "result" );
if ( not defined $result 
{
        $result = expensive_function();
        $cache->set( "result", $result, "1 hour" );
}
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