[SEJeff]

Well we used to be in the same boat and then... A new developer wrote a few new bit pieces of code that were supposed to work together. He overly unit tested each piece discretely, but they didn't work together. So when we pushed it out to staging and I manually tried to look at things, the entire design was wrong and would never work.

From then on, the next task said individual worked on was setting up selenium and write integration tests. Now we are in a pretty sweet place.

We have unit tests, which verify each discrete thing works as it is expected to and make refactoring large swaths of code a breeze. Then we have integration tests, which run on IE (in a windows vm that is on our build server), firefox, and chrome via xvfb. It even helps us catch those obnoxious conditions where javascript runs fine in "real browsers" and fails on IE's lameness. Give it a try :)