You may recall that I banged together a small application using Apex (nee HTMLDB) a few months ago. I got a call from a user the other day that something wasn't working quite right. Seems as one of the pages was giving them an incorrect result. I hadn't touched this particular application in about 2 months, but I knew it pulled information from a view I created just to make the Apex interface easy. The view called a piece of PL/SQL code that calculated a particular metric on-the-fly and due to some business rules, that calculation changed. It was a business-wide change, so I consulted the parties that use this package and we all agreed on the change to be made. I made the change and everybody was happy. I didn't have to get back into Apex or anything, just a simple PL/SQL change and I was done.
For those people that thought they had a better idea and rewrote the business logic in their Java middle-tier, good luck.