I used to dive right in and write without planning, but then teachers started making us hand in our plans and now it's weird to write an essay without one. Even if it's just a few lines.
There was a period where my plan was pretty much a complete essay but messier and missing one or two sentences. So yeah, don't do that.
I've become really scatterbrained so plans work well, even if it's just writing INTRO, PARA1, PARA2, PARA3, CONC with whatever ideas and dotpoints I can think of underneath. And I'll add to my plan while I'm writing if I can think of more ideas. This is also good if you're like me (please don't be like me, it tends to produce odd results + unnecessary stress) and like to write all 3 essays at the same time and not separately. (Intro of LA, Intro of Context, Para1 of LA, Intro of Text Response, add a few lines to my context etc. etc.)
LA is pretty structured so I just had to PEE (persuasive technique, example, effect) all over the article and that's my plan.