You must study and research, have a very LT time horizon and expect the unexpected.  

You will be surprised how much you can get rid of for free.

If you use all your nest egg unexpected repairs will put a hurt on you and create a lot of questions.

In this case, they didn't, so it would be no different than if they unexpectedly gave their notice to vacate.  

If you are looking to improve security with cameras (and I wouldn't just rely on the Ring for this) then just be sure you are not pointing any cameras in the home, do not record ANY audio and I used to actually note in my check in instructions that there were cameras for the guest and homes safety so they were not surprised when the arrived.  

I actually read this on the forum and was surprised to see my name mentioned usually I’d see that pop up in my email first so thanks for that!!!

The price of skilled labor as I understand it is about 40 percent of your costs, and in our area some general contractors have been rudely surprised in mid project to have skilled trades go to other states to do higher paying jobs.

I was very surprised to see how high the holding costs were though.

You WILL be surprised how much drier the crawl will be,,,but you always have moisture wicking up from the ground. 

None of these numbers were included (no surprise there).