Slight twist I learned from my wife: MoSCoW lists - Must, Should, Could, Won't. The "Won't"s really tie down the boundaries of the system. If your PM is smart

Slight twist I learned from my wife: MoSCoW lists - Must, Should, Could, Won't. The "Won't"s really tie down the boundaries of the system. If your PM is smart they probably won't call them "Won't"s, much more likely to bunch them into a column labelled "Phase 2".