After you're done writing your application, you're going to want to test it to make sure there isn't an abundance of bugs and other problems with what you've done.
Hmmm, not really very good advice. Automated testing after the fact is usually a losing battle. You don't have to do TDD, but waiting until you're "done" to start testing is going to be a painful proposition.
Seriously. If you're not doing the fulll-on TDD thing. at least get selenium in there early and bang on the site as you go to avoid some headaches later on.
It's easy to "finish" one part then never look at it again until you demo a site, and then realize you've changed DB schema or munged some template or model and shit falls apart.
Hmmm, not really very good advice. Automated testing after the fact is usually a losing battle. You don't have to do TDD, but waiting until you're "done" to start testing is going to be a painful proposition.