My basket of skills includes building/upgrading electrical services, separating basement wiring from the upstairs for a suite, installing wired security and camera systems and removing knob and tube. 

Knob and tube wiring - this can be an expensive fix and an insurance challenge.2.

You should not have a business model where your real estate investment will go down the tube (whatever that means) because your tenant moves.

If you are interested in this subject of Recession, as to likely play out in the U.S. real estate market in the 2020's; then there are 2 videos on U-Tube, to watch, doing so with a jaundiced eye, due to it is never how the seers say things will occur in the future.

When one goes to official government sites, they have their new addresses, but some of the other ones are not updated well.They did leave the house full of the sickest porn one could imagine....and filthy. 

Several books, hundreds of hours of you tube and podcasts and discussions with my wife we are buying our first investment property this September-October.

In response to the question, as to how hard the current 2020 Recession will hit, (there's 2 videos, I found on U-Tube, the last time I checked it, which I found on the right-hand side bar, of related videos to what I was seeking.

Knob and tube wiring, cast iron drain stacks, space heaters etc. 

I buy foreclosures and distressed, so during the initial rehab I'm always finding porn, drug paraphernalia, occasionally falling through rotten floors, evicting wild animals, discovering termite damage, etc. 

@Alexander Felice Awesome job with those you tube videos.