Wow, you've done a lot to troubleshoot it. 

So many better things to do with your time than deal with tenants having absurd expectations or requests or spending time troubleshooting trivial things.

I also recommend you keep an article or video on hand to help tenants troubleshoot problems.

Thanks so much for the follow-up question Joaquin, below is my understanding of what the sisters are most looking for in a property manager - if it's helpful to get into the specifics of what they haven't liked about their current experience, happy to do that offline :)Someone trusted and experienced with repair work and troubleshooting: More specifically, someone who can help provide them with a menu of options regarding fixes to the home that range from the "absolutely necessary" to the "nice to haves" and who, given the age of the home, can recommend "stitch in time" repairs.

Check the furnace again, diagnostic code shows the error and troubleshooting recommendations.

She saw how we operate and she even saw how me and my partner troubleshoot issues and resolve problems.One more investor decided to invest with us.

Look at YT videos on how to fix them or troubleshoot, so you will know key words to look for (and smell out imaginary cost-boosting terms like "a trap relay is unhinged"Make sure as much as you have is working.

They should be able to demonstrate the ability to troubleshoot, solve problems themselves, call a cheaper handyman, before calling in expensive experts.

You want to pick a service that understands: How to troubleshoot maintenance issuesHow to get contractors out during emergenciesHas a network of contractors to lean on (and at good pricing)Feel free to PM me if you want my suggestions on this.

As was posted above, I believe the most money is saved by troubleshooting problems rather than immediately calling in expensive professionals.