Drywall perimiter cavity, caulk?

Hello, I Wonder how to treat the cavity in the perimeter of the drywall facing the other walls around it, I'm aware of the caulk-backer rod-caulk-backer rod tactic, but I wonder how thick layers of caulk you can put in there? Is it caulk AND backer rod for each board, or is it caulk for one, backer rod for one, and so forth? Is it okay to put a 1" thick deep layer of caulk under approx 2 of the boards without backer rod in between? If it's one unison layer? Am I supposed to compress the backer rod a lot when installing it? Otherwise I would not be able to make the Caulk-backer rod per sheet technique that I've seen Knightfly uploading pictures of. Thank you!