We have already mentioned milestones and checkpoints are their to celebrate achievement and check progress. If progress is being stalled then interventions can take place to get the project back on track, so milestone events and checkpoints are essential along the way to achieving your Project Goal.
Record any observed issues in your issue log so that this can be discussed with the project team. If results are positive, the project can continue in the same way. If results are not positive, however, consult the project manager or sponsor about potential corrective action. This is an iterative process that should continue until you have achieved full implementation of the project and achieved the Project Goal.