I am learning PHP, AJAX, and SQL and have a long term goal of making a feature rich social website. I am leaning towards doing it from scratch because it will give me full control, seems a lot easier to debug, and I would feel better about security.
But I see people on the intertubes saying it would just be crazy to make such a website from scratch because it saves an enormous amount of time to use a CMS. I must admit that it seems handy that anytime I want a new feature, I can just grab a plug-in that is already written.
Experienced web developers, what is your experience? Is it a huge time sink to make a feature rich website from scratch?