In a scene heading that has a subheading such as APARTMENT, BEDROOM, do you use commas to separate or hyphens, such as APARTMENT-BEDROOM. I've seen both.

Personally for secondary sluglines, I would say that you don't need the APARTMENT at all. If the bedroom is in the apartment then it is unnecessary, if it isn't then APARTMENT is wrong!

To an extent, when you get to this level of detail, there is no right and wrong other than 'What distracts the reader least?' Keep the reader clear as to where they are without them thinking 'get on with it!'. All they want is to see your vision clearly.

It needs to be formatted correctly because a quick rule of thumb is that if you can't even be bothered to find out what the format is, then you haven't considered other things like the problem of a 10,000 person crowd scene

Ian

I guess the problem presents itself when there is more than one apartment...but I like your comment about what is least distracting! Thanks!

I would never use commas to separate the words in slug lines.

If you have a primary location, you start with that, and then just continue with the locations within the location, e.g.

INT. DAN'S APARTMENT - LIVING ROOM - NIGHT

The door opens and Dan and Lulu stumble into the living room, drunk and giggling.
They're already tearing off each other's clothes to the

BEDROOM

Dan's bedroom, where they collapse on the bed, and pass out, still half-dressed.

LATER

Dan snores, while Lulu gropes on the floor for her clothes, trying to be quiet.

==================
like that.

Perfect! BTW, the place I saw the comma was in the short screenplay found under formatting in this website in which they did:
INT-COFFEE SHOP - NIGHT
then a subheading like this:
INT-COFFEE SHOP, BATHROOM.
I think that was to show the action transferring from one part of a location to another. So I got confused. But all other examples I've seen are like the ones you've shown. So think I'll stick with that.
Many thanks.