Software Architect's Handbook

Last responsible moment (LRM)

The last responsible moment (LRM) is the strategy of delaying a decision until the moment when the cost of not making the decision is greater than the cost of making it. Design decisions made for a software architecture can be among the most important for a software system and they can be among the most difficult to change later.

With traditional software architectures, decisions were made very early in the project. In order to design an evolutionary architecture, it is beneficial to delay a decision until the LRM. This lessens the possibility that a premature decision will be made. Decisions that are made too early are very risky because they may end up being incorrect and then they will result in costly rework. ...