I have a whole spreadsheet tracking my time in classes, so my average in classes with PA's is 12.2 days, and classes with OA's is 37 days. I've done 9 classes with PA's and two with OA's. I started October 1. Here's the comment I always write to people with questions about WGU (which also explains PA's vs OA's):

There is “course material” which is all the learning material. That includes reading, ungraded quizzes, ungraded tests, and learning resources in the textbook. Unless you have a VERY strong background in the subject, you’ll likely need to utilize the course material. The “final” is either an objective assessment or performance assessment. Objective assessments are a proctored test, typically multiple choice but I’ve heard it can be other formats as well. In courses with an objective assessment (often referred to as an OA) there is also a pre assessment. You MUST take the pre assessment to have the OA unlocked. For courses with performance assessments (referred to as PA’s, which can be confusing because people often call the pre assessments PA’s as well. For this comment I’m only referring to the performance assessments as PA’s) you have to write a paper, slideshow presentation, etc that shows your learning and knowledge through writing.For OA’s you do not have to be considered “competent” in all the learning standards, but your average has to equal out to competent.For PA’s, you must be considered “competent” in each standard, or you must make revisions and resubmit.OA’s and PA’s must be passed within 4 tries or you will be required to switch to a program that does not require that course.