What is worth waiting for?

When we get nearer our public release dates, the question what is worth waiting for gets more and more important. And difficult. And at the same time, more easy. Today, we made a very rough estimation of the from the product owner perspective most important features. Things he found crucial for a release to customers. "We must have that, or we must have this." Well, must is a harsh word. When confronted with cost, musts becomes oh, no, can't wait for that. Or for those bucks we can get ten of those requirements. Mike Cohn's book on agile estimation and planning made a huge difference for us. Making the PO understand the cost of features. And having a tool for presenting this to non-team-stake-holders. When discussing with them, he doesn't talk about sprint points. He talks cash. How much a feature costs. And when sales says they want something, he can demand that they can bring in the extra money that will cost.