We can’t underestimate the setbacks and repercussions missing milestones can cause when it comes to a project. As others have already stated, it costs management time and money. Money may be negligible depending on the dollar amount, but time is something you do not get back. It looks bad on the company’s end to the customers that their are delays and customers may not take you seriously if it becomes a habit. Missing a milestone may also cause a domino effect for the timeline of the project and can cause delays in the rest of the other milestones and critical tasks to be carried out. Missing a milestone may be good if you’re doing more research regarding the project/product, but what about the rest of the project? Taking your time on one milestone means you’re going to have to rush on another milestone. Sure, you may have a better quality on that missed milestone, but reaching that same amount of quality for the next one is going to be challenging with an even smaller time constraint. It’s best to have all milestones balanced out when it comes to time and quality so in the end it results in a well rounded project/product. Project managers should account for these types of occurrences when making up the gantt chart and should keep in mind some milestones may take longer to reach depending on how much information they have or how difficult the tasks may be in order to reach that milestone.

Regardless, the only time I’d think missing a milestone would be a good thing is if you ended up using a budget well under the projected costs and are still somehow able to put the initial amount of quality into the next milestone.