Answer:

You can see which exams you are eligible for, when you can take them, and schedule your exam from the F5 Candidate Portal (http://certification.f5.com/).

Simply click "Schedule an exam" on the home page or "Scheduling" in the top-navigation bar.

This will show you a list of exams you are currently eligible to take under "Open Exam Eligibilities", giving you details for each exam.

You can schedule any exam listed under "Open Exam Eligibilities" and take the exam any date between the "Earliest test date" and "Exam Administration Ends" date (inclusive of those dates).

You can start your recertification journey 90 days prior to your certification expiration date. But, not before that. 

Example:

1. Click "Schedule an exam" on the home page, or "scheduling" in the top-navigation bar.
2. You will see a list of your open exam eligibilities:
   1. Name: is the name of the exam;
   2. Code: is the exam code;
   3. Earliest test date: is the first day you may take the exam;
   4. Exam Administration Ends: is the last day you may take the exam (inclusive);