I graduated with a BS in Microbiology 9 years ago. At the time, I wasn't sure what I wanted to do but took all the prereqs to become a Pharmacist, which is also the same prereqs to become a Nurse. My GPA is not the best, I had a lot of B-'s which dropped my cumulative GPA to 2.96. I had to repeat two courses because I got a C-, but after repeating them I only got a C because I didn't really know what I wanted to do at the time.
I am wondering how long my Prereqs are good for and if I'm going to need to take them again. I've been working in the Biotech field since graduating and now I want to pursue a BSN.
It is really up to the school itself. There is no hard and fast rule- so your best next step is to investigate schools that interest you and find out their policies.
For most schools in my area, all the science-y pre-reqs expire after 5 years. When you retake them, some schools will drop the old (expired) grade which would be a benefit for you. The only exception would be the accelerated programs which utilize cumulative (whole life) GPA. Check with schools in your area to get accurate information.