I've said for a long time that there are three phases of dungeon exploration as a player:

First, you are just entering the dungeon, and you don't have any solid information about its scope, denizens, or dangers. (This is the phase when players tend to be the most paranoid, checking carefully for traps, and so on.)

Second, you have a sense of the scope of the dungeon, but you haven't yet "mastered" it; there's still several unknown areas and, most importantly, you haven't yet encountered the "boss monster" of the dungeon--although you're likely to know who it is and what their motivations are by now. (This is usually the largest phase, time-wise, of dungeon exploration.)

The break between the second and third phase is usually the fight with the main threat, or "boss monster" of the dungeon. If the heroes are in the dungeon for a specific purpose--to rescue a prisoner, recover an item, or stop some event, they've done so.

Third, you have functionally completed the dungeon, but you aren't yet ready to leave; there are likely still several rooms you haven't yet ventured into or low-powered threats you haven't yet faced. (This is the part the GM is most likely to "hand-wave," saying things like "okay, you search the whole storeroom and find..." or "some orcs try to stop you, but you mop them up...")

I had a pretty specific lesson in this as a player just this week. In our Starfinder game, we encountered a seemingly derelict spaceship. Other than its appearance from the outside, we had no idea what to expect (and the ship's name was written in Ignan, so we expected fire-themed troubles). For the first few rooms, we didn't even have a sense of how big the ship was on the battlemap on the table. We moved slowly and carefully, each person putting their miniature exactly where we wanted it. We had a few fights, one particularly tough because I was reckless (and will remind everyone that my character is chaotic despite the consequences). Near the end of the session, we'd reached a forward room of the ship where we interrogated an enemy and searched through her belongings to find a lot of valuable information: where the "boss monster" was likely to be found on the ship, and what this boss's plans were likely to be.

We'd started in the first phase, and moved right into the second phase. That was neat to see. There's still more than half the ship to explore, but I suspect in our next session we'll complete the second phase and then do some easy third-phase clean-up. It's my dungeon exploration philosophy in action!

Keep these phases in mind as an RPG author. More specifically, keep in mind that your dungeon design can extend or compress these phases. Two examples:

* An underground dungeon might have a long time in the first phase because it's so hard to tell just how big a dungeon the players have gotten themselves into. Whereas a standalone building (or starship) often lets the players grasp the scope of the dungeon more quickly.

* If your "boss" is difficult to get to without going through nearly all of the dungeon first, your third phase will be very, very short.

Think about this the next time you're in a dungeon. Or in an unfamiliar Costco, maybe, as the principles of exploration are surprisingly similar.