Are you able to manage just 5 milestones?

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Graham Allcott, author of How To Be A Productivity Ninja, states that a perfect project plan should include five milestones. “Meltstones can become micro-management, or cause confusion and complication rather than clarity. In each project, you should aim for one to five milestones. Never more than five milestones, and never less than one.
Do you agree? I don’t. Let’s forget that for a second and let’s look at what he suggests these milestones should be. He continues, saying that the five-milestone model of projects is all that you really need. He then explains what these milestones should be. They are:
Establishment: This is the official recognition that the project has been set up with a team.
You can check the progress over the first few days to make sure that everything is moving in the right direction.
Mid-way: Checking progress at the halfway point to make sure you are still on track to reach your objectives.
Completion: This is the marking of the end of the project, based on the success criteria you established at the beginning.
Celebration: A time to recognize success, learn from the mistakes and give thanks to all those involved.
This model is likely to work well on small projects. It can be used for small projects with a small team. The work will be completed in a few months, if not sooner. This model is not suitable for anything that lasts more than 6 months, has a large budget, or involves more than 10 people. With so few milestones in your project plans, you will not be able track progress or make effective reports.
To be fair to Allcott, he briefly mentions the possibility of “complicated projects with hundreds inter-dependencies, where it is necessary to find the ‘critical pathway’ through all the complexity.” He suggests hiring an experienced project manager to handle all those tasks. “Old-style project management,” whatever that means, is not the best for daily projects. However, he does mention creating new brochures and websites. I like the old-style project management. It works well for all types of projects. However, you must scale it appropriately. This doesn’t mean you have to cut out all milestones from your project plan.
What is the smallest number of milestones you would want to have in a plan? Or is it really ‘it depends’ Comment below to let me know your thoughts!