When I have bought houses I have poked around the site while they were building them, much to their annoyance I am sure. I still haven't found all the issues.
My last house when I moved in just happened to be missing one lightbulb in a cupboard and one in the garage. As these weren't vital places for a bulb I didn't really worry about it, I did point out they were missing on the snagging list. Eventually I just put them in myself. In the cupboard it became immediately apparent that the light switch had been fitted upside down. I could have made a song and dance about possibly being electrocuted as I thought the light was off. When I put the garage bulb in, I found that they had never connected electricity to the garage. They had to dig up the garden to connect it up. I'll never be convinced that whoever put up the bulbs didn't discover these issues and it wasn't entirely coincidental that these were the only missing bulbs.
After Jeremy's comments re insulation I did look at the price of a IR camera for my phone, if they were a bit cheaper I would buy one to see what's missing inside our walls.
Edited by AliG, 28 November 2015 - 09:39 PM.