Don't take certificate exams.
The problem with certificates is that the usual process to get a certificate is flawed. Usually people study for months to get the knowledge to pass a specific certificate exam, and that's a problem.
Studying to get a certificate most of the times means that you are good at passing exams, not that you know about the subject per se.
The correct way to obtain a certificate is acquiring the knowledge with pure hands-on experience on the subject and then take the exam, at which point you would not even need to study for it.
But, most certainly, when you get to the point of having that much experience to get the certificate without even studying for it you won't even need the certificate to prove that knowledge.
And if you still need it to get yourself hired at a specific company, think if you actually want to work for a company that values a paper more than your hard gained skills and knowledge. If you still think it's worth it, then why not.