Lab notebooks:
Have a separate lab notebook or make drawings and notes all over the manual?
Carbon-copied prenumbered pages or a spiral-bound notebook?
Take them home to do the writeup, or leave them locked up in the lab?
Do your work elsewhere and copy it in, or print it out and staple it in, or record every piece of data by hand directly into the notebook at the time the measurement was taken?
Strike through a mistake or recopy the page?
On every one of these questions, each of my professors insists that the ways the others do things are wrong. It's almost funny to watch them put value judgments on these answers, all the while conflicting massively with each other. At least, it would be funny if the whole mess didn't have consequences for me personally. As a student, I don't get to be self-righteous and snooty; I get to OBEY. It's dizzying trying to memorize three different protocols. Perhaps the bookstore should hand out laminated cards showing the answer key for each professor. Not the answers to the homework or quiz problems, no; the answers to their particular brand of This Is The Way Everyone Should Do Things.
As the quarter wears on, of course, we're supposed to do all these things as second nature. It's like learning to touch-type when every day you get a new keyboard layout.
Homework:
Bother to do the problems or just write enough to show you know how you WOULD do it?
Turn it in during lab, during lecture, or not at all?
Are crossouts or white-out acceptable inside a pile of calculations (because We're Learning Here) or not acceptable (because This Is College-Level Work)?
Etc., etc., etc.
Round a 5 up no matter what, or round to the evens?
Work in groups in lab (because That's The Right Way To Learn), or work alone (because That's The Right Way To Learn)?
In France, when I lived there (1989), there were three different keyboard layouts in common use. In all the computer programming offices I saw, I met not a single touch-typist. My own rapid typing branded me as a bit of a freak.
no subject
Since you need to keep track anyways, type it up in a little table, with notes emphasizing the Dire Consequences of Doing it Wrong. Maybe leave some blanks for filling in additional professors' names later. Maybe print up a few extra copies, just in case one or two of your classmates can't keep track either. And if an anonymous copy should happen to make it into one of your professors' hands, maybe they'll get a kick out of it, and/or be a bit less snooty about it. (Just don't be too rude in the comments, in case it gets traced back to you.)
If you want to get serious about it, collect data from a few students who have other professors, and make the suggestion to the bookstore next term, with partial data already provided (and suitable disclaimers about how these are just some students' notes, and the professors are the Source of All Truth, etc). Laminated cards would be cute, but printed sheets can be updated with corrections or data on other professors.