Practically not all the requirements are always urgent and important. There will be many requirements which are desirable by the business but they may not be that important and urgent at that moment of time. Such requirements should be tagged as Good to have requirements.

Good to have requirements do not become part of the committed requirements, but a consultant can decide to deliver these requirements only if Must have and Should have requirements are developed and there is spare time available.

It is important to define this type of requirement, because if you deliver this requirement along with the other two requirements, to the business users, it will be an added service and it will create a good impression on them. It is like offering a full meal with dessert.

The MoSCow method also defines one more category of the requirement, which is Won't Have. At times this is also important, because a consultant needs to define clearly what can be delivered and what cannot be delivered. This helps businesses to have a clear idea about what they are going to get as a delivery of the project and what requirements won’t be included in that. This helps the consultant to avoid any confusion about the delivery of the project.