I spent this past 2 weeks applying for online lenders, and I've had millions (well, maybe a hundred) of phone calls from cash advance merchants that waste time and phone battery, and I'm pretty sure they will not stop calling me for at least 6 months. 

I had to install smoke/CO detectors with non-removable batteries before selling my condo in CA.

Running out of batteries means that I have to take a trip out to the unit, and I hate taking trips out to my units.

For example the cost of the module is $130k, and they told me my budget of $200-225k is "tight." 

They use a battery for backup, but if it beeps and they remove the battery guess what happens?

They use distance sensors and algorithims to map an area so they can go room to room on the same floor.They also roll themselves back to the recharging station when the battery gets low, and after getting charged, pick up where they left off.You can schedule it to run every day, every three days, whatever.Biggest drawback is that the dust bin is a little small.

Baby steps to more advanced over 9 modules.

Here's my experience: accept the Section 8 applicant, inspector comes about a week after; he's required to fail you based on one minor infraction, such as a loose wall plate, missing fire extinguisher, smoke alarm without battery, etc.

Locally We are adding Full solar with whole-home battery EV charging and Smart home compliance for the newest group of Renters who will pay extra for these features.

As I was writing my module on classified advertising and while doing the research I gathered "I Buy Houses" type ads in EVERY major newspaper published across the country.