What reminds you of the value of PMP?

If you are talking about the certification, the only thing it is valuable it is requested in some place as a requirement to get a new job. The certification is too far to make you somebody mature to manage a project.

Someone without a PMP certification may have all the knowledge or more than someone with it, so I don't feel the value is necessarily a measure of competency. I do however see that the majority of job postings for PM positions as well as technical leadership roles include, "PMP or equivalent" as either required or desired qualifications. The value in my mind is that having that 3-letter credential opens lots of doors by helping pass the screening process to get the interview where you have a better opportunity to explain your actual competency in detail.