I'm using Google Colab's free version to run my TensorFlow code. After about 12 hours, it gives an error message
"You cannot currently connect to a GPU due to usage limits in Colab."
I tried factory resetting the runtime to use the GPU again but it does not work. Furthermore, I restarted all sessions but this doesn't work either. Is there any method for me to be able to use the GPU again on Google Colab's free version?
If you use GPU regularly, runtime durations will become shorter and shorter and disconnections more frequent. The cooldown period before you can connect to another GPU will extend from hours to days to weeks. Google tracks everything. They not only know your accounts' usage but also the usage of accounts that appear related to your account and will adjust usage limits accordingly if they even suspect someone of trying to abuse the system. They will never give you an explicit reason why the runtime disconnected or why you can't connect to GPU other than the generic message about "usage limits". Neither will they ever give users a straightforward way to track their usage because all that would do is make it easier for people to skirt the restrictions. If your account is basically blacklisted they will never actually tell you your account is blacklisted because that creates more headaches for them. You'll just get the same message about usage limits when trying to connect forever. They prefer to have users confused and guessing because that keeps all the power with Google. And for a free service, who's to say there's anything wrong with that.
Edit: For Colab Pro they likely won't fatally restrict an account for over-usage but they can significantly restrict it by extending the cooldown period to 3-5 days, reducing runtime durations from 24 hrs to 6-8 hrs, etc. Keep in mind this is for people running multiple accounts multiple times a week for the maximum duration. If you're just using a single account once or twice a week you shouldn't have a problem.