Many Agile believers will tell you that the problems with pressure can be alleviated with Milestones. This is patently false. A solution isn’t valuable to a business until it provides notable business value. You may be 13 iterations into the project with 2 milestones behind you, but if the business isn’t deriving value, you haven’t done anything more than show them partially working software. Partially working software is great for building trust, but it alleviates zero pressure with respect to IDT.