She is in a managerial position in her employment (started a month ago), and although I'd prefer longer current employment history, having a managerial level job gives me a more reliable feeling about her.

If a contractor can provide these it is a good bet they are going to be reliable. 

I would like advice on how to get a reliable cleaner and caretaker (possibly the same person and possibly not) for a furnished vacation rental.I recently purchased a home in Fort Collins, CO, that I hope to convert to a furnished rental in late summer.

This is not a reliable service and a recipe for disaster. 

Everyone has them and they are ultra reliable.

why do they act like they are saving lives daily, like surgeons?

New hvac equipment is nowhere near as reliable as older stuff, new stuff doesn't last 20 years anymore and usually requires somewhat regular maintenance, it isn't as forgiving as it once was.  

I do Quality and Reliability Engineering for a Railroad (the day job) but my passion is Real Estate. 

You are better off hiring commercial workers on ground up, they are reliable and has more tools to increase productivity.

Carolina but between inventory running out and inflated prices, the deals there peetered out a couple years ago (and I never found an overly reliable turnkey provider there).- Dallas was a fantastic market about 2 years ago.