Dear exam aspirant,
If your question is referring to classroom teaching then let me put it straight to you that you can crack any exam of your choice without coaching. Going for coaching classes or not opting for one varies from person to person and absolutely depends upon your learning capacity.
An incident from the epic Mahabharat could explain it better. You must have heard the famous guru Dronacharya that was assigned to teach weaponry and martial art knowledge to Pandavas and Kauravas. Irony was that there were almost 105 pupils but it was only Arjuna that actually learnt archery to its core. On the other hand there was Eklavya, a Nishad prince (belonging to a tribal clan), who was not fortunate enough to have access to a guru like Drona and yet he was as good as Arjuna if he was needed to hit the bull’s eye.
A classroom coaching class from a good institute will definitely add value to your preparation but if you’re a working professional you’ll have to find ways to study being at home. But that’s not a problem in today’s era either. You can choose a good website or two that offer quality content with regular updates on topics like current affairs, GA, etc and give shape to your test preparation.
All the best!