Rodrick,
The answer to this question can be found on page 6 of the PMP credential handbook at
http://www.pmi.org/en/Certification/~/media/PDF/Certifications/pdc_pmphandbook.ashx
:
- After you submit the application PMI will do a "completeness review". This can take 5 days
- If your application is considered complete you have to pay online with a credit card. I recommend that you pay within 7 days.
- Once you pay you have 1 year to take the exam. (So if you pay on Jan 1st, you have until Dec. 31st to take the exam).
- If you are selected for Audit, then the 1 year duration starts at the end of your audit. (So if you pay on Jan 1st and the audit takes until Jan 28, then you have until Jan 27 next year to take the exam.)