Lots of older return air vents can end up in small hallways, etc where all the doors end up closed and isolating the vent itself.

Chris,Isolate every circuit and put a GFCI on each with a label NO EQUIPMENT GROUND.

Compared to leveraged real estate, this will of course be likely to underperform, especially if you can bring economies to the investment like managing the property yourself, etc.With regards to overall return, I believe that the 401(k) can no longer be looked at in isolation within a few unattractive (by our standards) publicly available funds.

I have also recently learned to isolate different aspects of my inspection process.

Recently, I had a similar issue with unresponsiveness (this is not an isolated incident). 

It's a special EPA training certificate which deals with how to isolate, contain lead safe areas during renovation and offer lead dust cleaning service and advice.

The villagers were surrounded by mountain passes which, in the winter, were closed off with snow, causing people to be isolated.

I doubt there is an isolated perceived difference in value if you are just talking about a stove vs a drop in range.You have to look at the entire kitchen as a whole.

Paint job, roofing, isolation, windows etc.

I definitely need to isolate my area of focus because as you mentioned, and as I've looked more into the different platforms, they cater towards different areas/ styles of investing.