Pipes and electrical boxes. It's amazing that these guys know what everything connects to and that when it's all installed everything will work as expected. Probably why we're paying them the big bucks.
The fuse box at the back of the garage, along with the drainage pipe.
Lighting in the studio, or at least the wiring for the lighting.
This week I also picked out flooring, bathroom fixtures, a work sink, and cabinets for around the work sink. This coming week the insulation will be installed and then they can begin hanging the wall board. Also the siding on the outside. I think the end is in sight. Hopefully it arrives before we run out of money.