system
Given the following post, respond as if you're commenting on Reddit:
human
Would I have to retake classes I’ve already taken in my MS for my PhD?

Suppose I take several graduate classes in a subject for a MS and after getting the degree, I jump into industry for several years (say ~5 yrs). If I decide to pursue a PhD in a closely related or the same subject and some of requirements for this PhD have already been met from my MS degree, would they still be eligible for consideration despite having been taken years ago? As such, do credits expire? Do you typically have to give a test proving you are knowledgeable of those classes or do you have to repeat them?

I know this would vary a lot from college to college but I just wanna get a general idea since its too far in advance for me to even have an idea as to what graduate school I would go to for a PhD. 

P.s. The subject in question is mathematical finance.
gpt
Credits can expire. The rule is set by the university, so you’d have to contact them specifically to ask. They also may not accept your specific courses because they don’t think they match their courses closely enough, and if they’re mostly 500-level they may not count them toward the Ph.D at all.