When an E-4 calls me "hey" or "hey man" knowing that I am an officer, should I bother to correct him?

I enlisted and was discharged as an E-4. I never would have imagined addressing an officer as 'hey' or 'hey man.' Correcting that behavior promptly is crucial, as it reflects a lack of respect and can be the first step toward insubordination. It's essential for individuals to understand that they've joined the military, not a regular 9-to-5 job.

In what context are you interacting outside work? It's possible that someone else unfortunately set a bad precedent that you now have to correct. I think because he is using correct C&C at work, there's no need to "light him up" but rather remind him that they are supposed to extend beyond the workday. There is a way to enforce standards without antagonism, and I've found that to be more effective

Yes for Sir.

Take this for what you will...

I was an E4. Never. Absolutely never called an officer hey man. If in public outside of work I called them Mr/Ms/Mrs or sir madame. Even the ones I had intimate working relations with. Being on a 110ft ship you got to know your cremated WELL.
If this is something you intend to give thought to then it bothers you. And it's not correct.
What you permit- you promote.
Pull the 4 aside and have a chat. Seek them out at work and ask to speak. Doesn't need to be an official scolding just more of a "hey friendly reminder" contact. You never know...he may have had an officer in the past or previous command that set this norm for him. Or he could just be a sandbagger and need some correction.

The Specialist is way out of line. Off duty or not. He's aware of your rank and should address you as such. On the spot correction.

There's a tradition in the submarine world that enlisted with dolphins, warfare qualified, don't salute officers without dolphins. Yeah. Bring prior enlisted, I had those boys locking heels and standing at attention until they gave me a salute. I wasn't popular for awhile, but word got around and that was fixed on our sub.

If he's calling you "man" or "hey man" when outside of work--especially when you are both in civilian clothes, but calls you "sir" while at work, what is the issue? "Hey" and "hey man" are kind of loutish ways to address someone, but anyone who has been in the military knows how to swear in paragraphs without being redundant, so there are a WHOLE lot worse methods of address that guy could use when he's off duty & out of uniform.

Most definitely correct him or her on the spot. We have to keep up the standards or they slip and there is hardly any way to reinstitute that standard if you fail to hold up your side.

Seriously? At the minimum they absolutely have to respect the rank. As an NCO, that person knows better, it’s not like they joined yesterday. Back on the day of I would have tried that it would have been an instant Article 15. Have more respect for yourself, sir, and correct those who need it. If you let that trash perpetuate, your troops will not have an ounce of respect for your authority. You have no reason at all to fear them. Take charge, you’re an officer.

Yes sir! He knows you are an officer...pull aside and correct him. If he was in uniform and had a cover on that "GORD" he is required to salute you. Civilian wear does not change things when knowing you are an officer. Per the MARINE CORPS. Semper FI.