Teachers and TA's , how often do you give students a grade for their papers without reading most of it?

Honestly, I think anyone who says they read every single word of a hundred papers is probably lying or has way too much free time. When I was going through my own degree, I noticed that most graders develop a pattern pretty fast. They look for the thesis statement, check the first and last paragraphs, and skim the middle for key arguments or evidence. If the structure is solid and the writing flows well at the start, you can usually tell where the grade is landing without needing to analyze every single sentence.

It’s not necessarily about being lazy, it's just about efficiency. Once you've read fifty papers on the same prompt, they start to blend together. If a student clearly understands the concept and presents it logically, there's no real point in nitpicking every comma. I've heard friends who TA mention that they sometimes spot a major logical error early on, and once that's confirmed, the rest of the paper is just confirming the grade they already have in mind.

I wouldn't stress too much about it if you're writing decent work. If you put in the effort to make your points clear and organized, the person grading is definitely going to pick up on that pretty quickly. Most people just want to see that you actually engaged with the material rather than just padding the word count with fluff.