How can we limit it?
- Determine all stakeholders and get their input into the project at the start of the project. This is key to defining the scope of the project.
- Make sure all the stakeholders review and agree to the scope.
- Break down the WBS far enough to cover all the items in the scope.
- Have a change control process and make sure your project team members understand it. When a possible change comes in make sure you investigate it (is it really necessary?), come up with options, and then present it to the change control review board.
If you keep this in mind for your next project you may just keep Creep out or at least have a means for controlling it.