As I'm reading the PMBOK or Rita guide for the PMP exam, I learned that schedule comes before the budget planning. Can anyone tell me why it has to be in this order? Is there something in real project work that makes you do the schedule before you can do the budget? (I don't work with budgets much, so I must be missing something). Or is it just only when you learn how long something is going to take, and how much that resource will cost to do it, should you start working on the budget? I know there is some dependency on each other (e.g. schedule overruns can increase budget). I'm a bit confused because sometimes you start of with a project budget prior to doing any planning or during the initiation phases, hence my question. Thanks!