I've been doing checkpoints here and there throughout the year but for bio it's extremely content-heavy, i keep up to date with my notes/content for my sacs and ultimately for my exam but is doing checkpoints even necessary for exam prep? i have less than 2 months away till my exam should i just smash out as many past papers as possible till exam and consolidate what I'm constantly getting incorrect in?
checkpoints are exam-style questions mixed with some actual exam questions soi think they're pretty good for exam preparation. There may be some irrelevant questions on there, but as long as you know your study design, you should just be able to skip those.
Obviously, doing exams are the best exam preparation, but there are only so many practice exams out there, so depending on the speed at which you go through exams you may find that you run out of them. In this case, checkpoints would indeed be a good resource to help you space them out. However, if you plan on going through exams slowly, you may not need to do any checkpoints. Maybe start doing some practice exams and see how you end up going.
As a bit of advice on the side, I would highly recommend not rushing through practice exams too quickly. It is really important to go through and mark yourself honestly and really analyse your mistakes. I would recommend re-writing any incorrect responses or any responses that were a bit borderline/weak and trying to determine why you answered it wrong (i.e. is it something you don't know? did you rush and leave details out? did you not read the question?)