Once you have received your PMP certification, PMI requires that you make an active effort to keep your skills and knowledge active in order to renew the certificate. PMI requires you to prove that you continually expand and maintain your project management knowledge.
Therefore, you must collect 60 PDU (Professional Development Units) points over a period of 3 years. The points that are collected by varies activities like going to conferences on project sharing, writing articles on project management, teaching project management and reading books on project management. The points must be documented at the PMI website.
Three years after your exam, PMI counts your registered points. If you have 60 or more, they issue a new certificate. If you do not have enough points, your certificate will be withdrawn and you will have to go to a new exam to be certified again. You have three full years to collect points, so if you have been to the exam on May 15, 2016, your first PDU period ends May 15, 2019.
From March 1, 2011, the PDU rules have changed - read here (.pptx) about the new rules and see how to easily register your PDU.
You can read more here or see the information video here.
If you have questions, just write us: vpcertification