For mostly every task I've had to accomplish, a simple text editor with syntax highlighting had been more than adequate. The problem comes when your project becomes bigger and you need to refactor that one proc which had been used everywhere, or stuff like that...
It is also very useful when you change something in your code thinking for the best and you find you've broken some proc call in a remote script you would have never thought about.
In general, I feel the lask of an IDE when it comes to maintainance...
