| requirements creep | very significant cost overruns in projects | - using incremental development
 - carefully documenting  the problem boundaries at an early stage
 -  estimating the time any proposed requirement will take
 - . deferring major changes to subsequent releases if possible 
 
  | when changes to a system are really enhancements in disguise | process | 4.9 - Managing Changing Requirements | The tendency for the set of requirements to relentlessly increase in size during the course of development, resulting in a system that is more expensive and complex than originally intended |