Do you use pre-created rooms when building?

I've only used them in one build. Normally I build everything myself from scratch because I love building/decorating. In this case though, I was in a hurry to start playing a challenge and didn't need to be fussy about the build. However, I did change the object positions around and switched some of them out for other similar objects. Actually, in the end, the rooms didn't look very much like the originals. Oh well, at least they gave me a good starting point for that build and saved myself a little time. :)