• Most common thing I do in <Perl> tags: use lib (...)
• Funniest thing I've ever done in a <Perl> tag: assert that the httpd is not being started by root. Because our typical production environment (from which we template our development configs) will setuid to httpd.nobody (fairly standard), but developers' httpds should run under their own UIDs (and if not started by root, they can't setuid... so all is happy!).

As to your note at the end, that you are considering preopening a DBI connection: don't do that. DBI isn't fork-safe in that manner (at best, you'd be able to use the connection in one of your subprocesses). Instead, you should use Apache::DBI, which lets your subprocesses connect once, on the first request, and hold the connection open for future requests. The connections do have to be one per subprocess, though, so no connecting before the fork and inheriting connections... sorry.