So, been thinking about dwarves, and architecture. Now when you live underground, in proximity to the underdark, with all the horrors lurking and creeping around your doorstep; there ain't really gonna be a hard limit on how many barred doors, turrets and arrow slots you're gonna have.
Yet, to make something impregnable, you end up making it vunerable in other ways. For instance, one could argue that the most defensible position only has one entrance. But that ends up being a fire hazard. Granted dwarves tend to build mostly out of stone, so not a whole lot of it can burn, but stone chairs are impractical in that they can't hardly be moved and would give hemoroids so eh, not a good idea. Same with most kinds of furniture. And in either case, fire isn't the only problem. If something bad enters through the one entrance, it's going to be hard to get out.
If you make something safe from gas, you run out of air.
If you make it so you can shoot out, that's potentially a place to shoot in.
Now dwarves being all about defense, but also extremely pragmatic and practical. One begs the question where to draw the line, it seems something has to give.
There's also the whole, what parts of a house becomes obsolete when you live in a cave. I figure caverns still have drippings and what not so a roof, and a curved/sloped/domed one at that, isn't too bad. Windows though, might not be all that important, at least not from a light standpoint. Plus they're natural weak spots. My home is my castle after all.