I worked for a hotel software company in 2006. I was the Lead Architect (read, the only one who had any knowledge of it after its creator left the company) for the Sales System. The Architect I had inherited it from had used a cheap code generator to create most of the classes. His "framework", instead of using normal JSPs consisted of Java classes that read in an HTML file and ran replaceAll to substitute the record variables for placeholders in the HTML file.
The client (a VP) asked me (on December 11th) how long it would take to rewrite the bonus application to use a new algorithm to calculate bonus eligibility and amount. I told him 6 months. He said, "Yeah... that's not going to work for me. What would I have to do to make you change your answer to "I'll have it by January 1st?"" I said, "You can build a time machine, go back to July, and ask me then. Otherwise, it'll be 6 months, since I am rewriting one of the largest pieces of the software."