I want to upgrade Apache, I'm a few versions behind (Apache/2.2.12) and I want to add mod_ssl. Do I need to recompile PHP? I also use the APC PHP extension - if I need to recompile PHP, will I need to recompile APC?
Safest answer: if you recompile Apache you should recompile PHP (and APC.)
Longer answer: you might be able to get away with not recompiling PHP (or APC) if nothing that mod_php depends on changed between Apache versions. mod_php should only be using the public Apache API and that doesn't tend to change between minor releases (from 2.2.12 to 2.2.13 for example.)
In all honesty, it's likely more important to keep PHP up to date given the various security fixes present in each release. So, if you're upgrading Apache consider it a good time to upgrade PHP (and APC) to the latest stable releases.