I've done lots of troubleshooting and no change in results.

I also recommend the episode "Case Study of an Airbnb in Cape Town" because it troubleshoots someone's listing that is not doing well.

For a gas leak, the trouble shooting its hard to figure gas pipe leaks but personally it would be worth the peace of mind to me.  

You learn what to expect from them, They learn what your expectations are, AND, they learn about your property so they do not need to "investigate" every time they visit the property to troubleshoot or locate features.

I would question 3 visits prior to install, but depends on the symptoms and repairs or troubleshooting done during those visits.

My only complaint is that it has now twice disconnected from the wireless hub and I had to have my housekeeper do some extensive troubleshooting to get it to reconnect.

If it was yours, next time let the service person troubleshoot it.

I'd look for:An ability to troubleshoot maintenance issues on the phoneAn ability to send a good contractor to fix emergency issues (anything that can cause property damage)Feel free to PM me for details/suggestions.

They should have very good troubleshooting skills, both for talking a Tenant through a problem that avoids any cost to Owner, and so they understand what contractors are actually talking about on projects.You do also need to realize, THEIR systems are just that, they may be inflexible in some, but not all, areas.

Since they have battery, have you tried without the hardwire so see if just one of them is a problem --- yeah, you've already got replacements and done your own troubleshooting..Not sure how the interconnect wiring works, but could it be possible that wiring has a short somewhere?