Effort = Time or The Mythical Man Month

Everybody involved in software engineering knows that the same effects occur every time. Since decades.

Some interesting Ideas of the Book The Mythical Man Month are presented on the Wikipedia page of the book.
http://en.wikipedia.org/wiki/The_Mythical_Man-Month

• Assigning more programmers to a project running behind schedule will make it even later
• The second system an engineer designs is the most dangerous system he will ever design
• Think Big - but milestone small
• The chief architect SHOULD write an end user manual
• too many meetings or sick leaves
• don't assume. communicate!
• hire implementers AFTER architecture completion
• don't implement if you can buy it "off the shelf"