For those that don't know it is an alarm system you can install yourself.  

We had tenants who had a situation that made them pay the rent in installments for a short time but that is working with someone with an issue.

You won't be able to buy and have a new one installed for less than $150.

Did you give permission to her to install the tile?  

I change the HVAC filters twice yearly, plus I provide & install the smoke detector batteries.

It doesn't start adding up with leakage over into the next month.Example January 1,200 ( pays 1,000 in two payments ), 200 leftover for February and now 1,200 + 200 = 1,400 owed ( pays 1,100 in  2 installments), March now 1,200 + 300 = 1,500 etc.This creates a situation from where the tenant cannot recover.

I were think about installing burglary bars but  that is a fire hazard?

Within 4 days of move in, there was a major leak under the master tub...big enough that the foyer ceiling below (original plaster and lath) was cracked and sagging, and then it somehow dripped all the way down into the basement and soaked a large section of the basement ceiling as well.Luckily, we had already hired a plumber (prior to them even inquiring about the house) to install a back flow valve as part of the city's sewer upgrade.  

Someone on another forum suggested to DIY with Termidor, but I've read that you can't even get termidor on your own, and then I wonder if there would be issues with doing it correctly, as well as liability.What do people on here do, get a one time preventative treatment, or wait until there's visible evidence of termites before doing any treatments?

[I pay about $2500 installed for a new gas furnace and central AC.