You are being too lenient and you are also showing preferential treatment, all tenants must be treated equally.

I know when I was a tenant my landlord made me hire professional cleaners, carpet cleaners and flea treatment, etc with receipts.

They are not entitled to any special treatment beyond their legal rights.

HVAC, painting, pest-treatment, handymen... you name it.

Let her know you covered pest treatment last time, but in the future it is her responsibility.I would not recommend a house warranty.

She is saying that she's had cancer (melanoma) and that the sunlight can be harmful.

If they are German roaches, a few days after treatment, you have to go in and clean up the dead bugs.  

The best treatment for me has been this forum!

It will ask the medical professional if the tenant:1) has been under their regular care for treatment of their disability;2) that the tenant meets the HUD definition of disabled;3) that they require a companion animal in order to be able to live comfortable in your unit, because of their disability.You have every right to require them to meet the definition of disabled and to have a bonafide medical professional verify that they are disabled and require a companion animal because they are disabled - in order to be able to live comfortably in your unit.If the go to HUD and complain that that big meanie landlord didn't let me have my two "service" dogs, HUD will not immediately believe them.  

I have been doing it for years and have a treasure of info about market rent, deposits, utility treatment, PM's, owners, pet policies, average stay, and empty days.If I were you I'd aim to have two months of mortgage payments liquid, and a plan for how you can quickly come up with two more months if needed as a safety net for unexpected repairs, lost rent, etc.