I would have to say, that a great amount of time is spent literally understanding home automation, and trying to come to grips with the functional scope of the system.
I have been doing smart home research since the late 1980s (my father and I started doing advanced research on this topic in 1986), so I had a serious scope of what to buy, etc, when I first stumbled onto this project...but I spent my first chunk of time studying the code to see what it expected hardware wise, etc.. and once I knew what worked best, I put my system together very quickly...
I do admit, that I am one of the core devs, but I wasn't always a core dev, and I did have to start from scratch.
But I can tell you, that if I had to move into another apartment, I could have the LinuxMCE parts of the home set up in about 4 hours from beginning to end. Most of the time would be spent installing the various sensors, cameras, lighting modules....
-Thom