How often do you use the pre-built rooms?

I used them for my first legacy when I built what I started calling “nightmare house.” I’m not a builder, so whenever the family had the cash and needed an additional room, I’d pop in a pre-built room. I decided I’d keep track of all the completed careers by adding in the career room once a sim unlocked it. The result was a maze of long hallways with random, but nice rooms; it earned that nightmare designation by being a pain to move through. The rooms on their own looked nice and saved me a lot of time furnishing things.

Now I just download whole builds off the gallery so I don’t need to use individual rooms. They’d be more useful to me for remodeling purposes if I could tell how big a room would be (and where the windows/doors are) before I tried to place it somewhere it won’t fit right. I’ve always preferred the style of the individual rooms over the maxis premade houses; maybe it’s just the exteriors I don’t care for.