Is it necessary to write an essay strictly due to the required structure? We'd been taught the structure in school and uni, but is it really necessary to stick to it?
Depending on what kind of essay or paper you're writing, there should be a proper structure to follow and yes you should be following it. Otherwise more often than not your work is going to turn into an unorganized mess.
You don't have to stick to specific structural details to the dot, but generally yes you should follow them.
You're taught the basic tools on how to structure and formulate your arguments in schooling. It's on you, however, to come up with your own style and organization. Don't be afraid to take risks and to set yourself apart.
You learned fundementals only, now you can right your own essays the way you like as long as you have sense writing them down, and organize your thought process.
Writing question
To just start writing again. After I did some paid work, I had little time to write fun stuff. Then felt really burned out when the work dried up. Ive started to get the itch again. Well see what happens, but Ive been thinking about jumping into the Challenge again for awhile now.
If you want to write differently, do it. Usually people stick to the classic way, because it's easy to understand. But if you can structure it and the message is still clear, do it.