Those who get good grades, do they study even if they exhausted?

You know your body and mind best. You have to find out what works for you. Experimentation! A friend of mine studies only when they're exhausted and get fantastic grades. Me, a different kind of good-grade-earner, on the other hand... I never learn anything if I bulldoze through study when I'm exhausted. However! I take a 20 minute nap then start studying. If it's short enough, I study a chapter or quiz (or, if it's too long for that, I study 20ish minutes), then take a ten minute nap to digest it, leapfrogging sleep and study. Nothing compares to a good night's sleep. Take care of yourself, Beloved.

No. Studying is important of course, but you need to take care of yourself first and foremost. It's hard to pay attention in class and focus on your homework if you're always tired. By all means, work hard, but if you feel that you need to sleep, do so. Same goes for eating, hydrating, taking a quick break, and anything you need to do to stay healthy, because your health and wellbeing are more important. Good grades are attainable without burning yourself out.

If I have an exam in a class that is extremely difficult, I will study even if i’m exhausted. However, If it’s past 2 am, I usually just give up and go to sleep and then wake up early to study before class.

Hell no! I just graduated school as the best student from my class. My "secret" was, that I took regular breaks and planned time for things I like doing. I also put away all my books after 8pm. Of course, during my planned study time, I studied. No excuses allowed! I switched off my phone, put away my laptop or switched off the wifi and just studied. I started early enough and planned to study around 40 hours per subject per exam, depending on the size and importance of the exam. Sounds like much, but if you start early enough, it's not that bad. But due to the fact that I also had time for doing stuff I like and getting enough sleep, I was less stressed then others before exams and so had a better chance of remembering the stuff I learned.

Whilst study is important, it is also important to rest and not to over exert yourself as this can cause stress which can affect your studies. Those who get good grades tend to set aside particular number of hours each day to study certain subjects. This helps develop a routine which can make studying feel less daunting.

Maybe some, but not everyone. Your brain needs time to rest and switch off from studying, it makes your ability to retain information and recall information much more efficient. If you're pushing yourself to study when you are exhausted, you may not only be diminishing your ability to retain & recall information, you could also be causing harm to other parts of your brain which may cause more stresses for you later on. It is important to take time away from your studies to allow your brain to switch off and some of the best ways to do so is to engage in hobbies, socialise with friends or even take time to meditate. Whatever works best for you is all that matters, just ensure you're taking time out to take care of yourself too.

Honestly speaking from experience, no. The key to doing well is working smarter not necessarily harder. They usually space out their work, and try to start assignments earlier rather than the night before/day of. They also might utilize office hours (if they're in college/university) or ask their teacher any questions if they have them (whether in person or email). They have methods that work for them and they stick to them unless something changes. What does this mean for you? Try to schedule out assignments, break things down into more manageable tasks, and take breaks (not frequently, but often enough). Those last tips should be enough to start finding methods that help you to get good grades.

Some people are different from others and require little or no studying to get good grades, but some do, I do. I motivate myself and I know how overwhelming it can be, but it is not advisable to stretch yourself to study even when exhausted. I do this sometimes and most times it's not worth it, I study for hours then end up getting a grade I don't like, plus it's not mentally healthy. You're mental health has to come first, and forcing yourself to study even when tired can negatively affect you, but as I mentioned before people are totally different.