Hello !
I'm re-plumbing my house (3 stories on a basement) and am trying to consider ease of future maintenance in the dwv design since at some point there will be a couple of tenants living here as well. What are your thoughts regarding the following:

1. Installing a test tee directly below the sanitary tee draining the lavatories? I could see this possibly being more useful on the 2nd and 3rd floors as we're further from the combo and clean out adapter in the basement serving each branch.

2. The trap arm (2" pvc) of my kitchen sink runs horizontally under a window. I was initially thinking I'd simply turn out of the wall with a 2" sweep 90 for the 1.5" trap. Then I thought about using a combo to turn out of the wall (probably about 8" off center of the sink) and then continue on through the combo to the other side of the sink cabinet and then sweep 90 out into the cabinet and terminate with a clean out. Is this worth the effort or is any clog probably going to be in the trap anyway?

3. Is there anything else you would do on your personal house to ease maintenance?

Thanks so much!