D&D 5E How much fighting do a typical D&D session have?

[Sotik]

A rest between sessions is convenient, though - it's intuitive, and it reduces bookkeeping from one session to the next, as each PC is fully re-set the next time you meet. You might have to worry about some un-recovered HD, that's about it.

A short rest between sessions wouldn't be quite as convenient, that way, but if it fit the pacing/length of sessions better, why not?

And, of course, a session with a hard stop could end in the middle of the action, even the middle of combat...

This is true, it really is hard to gauge these types of things when it comes to D&D for the very reasons you brought up. My group goes for 3 hours, and when those 3 hours are up they want to stop even if they are in the middle of combat.

That's why I heavily suggest not to worry about what the RAW "suggest" and just go with what makes sense at the time. If your group is in a dungeon crawl that might take 2 real life sessions to complete, then for the next 2 sessions you have 100% combat unless they leave the dungeon. If they are in a place where they will be talking to a lot of NPC's and progressing the story line, then you very well may have a session that is 100% roleplaying. Long as everyone is having fun, and you as a DM mix up the RP and combat making it interesting, it shouldn't really matter if you are meeting the RAW status quo.

Also all of this is heavily dependent on how the group handles stuff. A great example is the mini session Acquisition Inc did. I am sure that Chris Perkins expected there to be a whole lot more combat than there was, but Patrick Rothfuss RP'ed their way out of a ton of stuff.