In BP-style, I am largely left to my own devices to determine how solid the offering is -- I do my own due diligence and that's that.

As ane example, Nest has all sorts of devices that can be linked to one account. 

Oh, sorry about that, @Patti Robertson .Do you access the site through a mobile device?

It's the only proof of income they provided us, period.If they made $50,000 since February, I still wouldn't accept a screen shot from a mobile device as evidence.

@Chris SeveneyWhen others suggested devices to track temperature, I immediately start searching wireless thermostats.

Pool FLOATS encourage people to swim who shouldn’t necessarily be swimming, therefore increasing liability exposure even more I bet the HOA’s insurance company advised the HOA to toss all pool floats that weren’t official life-saving devices. 

Most of my prospective tenants are 30-somethings and want privacy and wi-fi, preferably high-speed...So I have tried a little device that plugs into the wall outlet that is suppose to reach other connections...but it does not work to the house in back...any other suggestions.

Ring doorbell and a cellular wifi device.

At a minimum, photos of receipts should be stored in a cloud drive (such as Google Drive) that you can easily access and upload with your mobile device. 

See if you can get a device to lock it out in off position.Video telling her to leave it off and you will check it once she is out.