What is the proper way to address NCOs in different branches?

Recruits are required to call their Drill Instructors "Sir". But after boot camp all enlisted marines are addressed by their rank

Personal experience: As a Marine, I was trained to use full rank. I was on an Air Force base for tech school and even though I didn't have to, I used full rank. The AF NCO's seemed to really like that.

I started out as an enlisted soldier in the Army. We only addressed officers as sir or ma'am. The NCOs, we called them Sargent from E-5 through E-8, unless you were a First Sargent. E-9s were addressed as Sargent Major. We didn't dare call any enlisted sir or ma'am. When switched to Air Force, I was shocked to hear the enlisted being called sir or ma'am. Being that I am a soldier airman, I call the NCOs Sargent, E-5 through E-8. The E-9s I address as Chief. I never address any enlisted person sir or ma'am, only by their rank.

Recruits address every Marine enlisted or Officer as sir or ma'am until they have earned the title of Marine. After they have become Marines they address fellow Marines by their rank and last name.

Recruits in Marine Corps boot camp call everyone Sir. If they didn't, they would be destroyed by their Drill Instructors. Once tte Recruit earns his Eagle, Globe and Anchor, they call eeveryone who is a higher rank than them by there respective rank. As a soldier addressing a Marine who is higher rank than them is the same way. It's all about respect. Marines do the same thing.

Marine recruits use sir to address an any Marine only in recruit status. Once Marines earn their E.G.A s they are taught to address Marines by their rank or rank and last name. In the Marines we usually just learn the ranks of other branches to make fewer headaches in the future. At first it can be some rough seas not knowing the ranks but after a while you have issue addressing any service member by their correct title. Even foreign troops.

I didn't realize Gunney was a "only when you know each other" kind of term. Thanks for the lesson on that.
I remember working in an office setting with two Army E7s (SFCs) when I was a 1LT. They always referred to each other as Sergeant Jones and Sergeant Smith. I finally asked them..."If I wasn't here, would it be Jill and Melissa" (I used their actual first names when I asked the question, but I don't remember them now). They told me yes. I thought that was interesting.
I worked very closely with a CW3. He was adament about being called Chief. We'd occasionally get soldiers from other units in our area who were not sure what to call him and they'd start with Sir. He always told them (in a fatherly way, not a butt-chewing way) that the LT (me) was Sir, but he was Chief. His other peeve was when he'd hear of a WO1 being called Chief instead of Mr.

A Marine recruit is not a Marine. In fact, a recruit is nasty, worse than a civilian because they have the audacity to aspire to be a Marine. Therefore they address all as sir or ma'am.
Once a Marine actually becomes a Marine, then enlisted Marines are addressed by rank.

Years ago when I was and army E5, I was assigned to the ID card section. A USMC Staff Sergeant came in to get an ID card. I addressed him politely as 'Sergeant' and he proceeded to correct me in a very derogatory tone, "that's Staff Sergeant'. Now I was a good NCO being respectful in my office. Perhaps I should have know how to properly address this NCO, but I made a mistake. I felt his tone was out of line and within moments my system 'crashed' and I could no longer help him. Moral of the story: do your best and be respectful and if you do make a mistake, the other party should have the decency to either let it go or politely correct you.

Correct me if I am wrong, but I think that in training, the cadre are called sir by the trainees.