I am currently putting up external cameras, have signs asking guests to respect quiet hours, have ordered a decibel monitoring device, and have visited with the police to explain I do not cater to parties.   

I have done very well, but it's been by buying at a discount, being very conservative with repairs, accounting for cap ex, getting repairs done cheaper than the other guys (I own, for example, a commercial snake, line locator, camera, etc.), rehabbing with an understanding of durability, and, if I'm being completely honest, quite a bit of luck due to an appreciating market.

The remodel included the following labor and materials included:1300 sqft addition to an existing 1700 sqft homeA new roof was installed2 4 ton ac units with furnace were installedA complete home repipe with copper and a new tankless water heater installed80 recessed lights installed, 75 new outlets, 25 new dimmers2800 sqft of enginerred wood floor installed along with new baseboard 4 complete bathroom remodels from a-zComplete kitchen remodel with 22 cabinets, quartz counters with a waterfall island and full backsplash quartz wallsNew garage door, along with a new driveway, and fence installedComplete exterior landscape with over 100 plants and 10 olive trees installedRaise an existing 8 foot ceiling to 12 feet in the living room25 vinyl windows installed with moldings4 new closets installed15 interior doors installed 3 patio sliding doorsBuild a 150 sqft deck outsideMarble fire place with custom mantel Demo and disposal of all project materials 250 sheets of drywall hung, sanded, textured, and complete interior painting$5000 worth of new appliances$7000 worth of cameras, speakers, smart home featuresNew stucco to exterior of home, plus siding$15,000 worth of permits, plans, site plans, city fees

Curb appeal, lighting, possibly security cameras, solid core or decorative metal doors with deadbolts and security screen doors, interior painting that is not one color on everything, accent walls in main living area and primary bedroom, cabinets and closets painted white on the interior, flooring limited to one or two designs throughout the unit, and no carpet, windows and screens fully operable and clean...all of this will elevate your unit vs. most of the others in such a neighborhood.

Ring doorbell or similar camera to check on who comes in and out, and smart thermostat so you can change the temp before guests arrive or when they leave.

I suggest you change the locks, give her keys, and have her buy some security cameras that she monitors through her phone.

Much better than what I currently have.I’ve actually thought about putting a camera up in the parking lot to capture how often the car is there.I’ll start with the written letter first reminding the tenant of the lease.

I just bought a new camera to do this with!

@Brandon Alexander You can do some of that today on properties you own with internet monitoring(alarm) systems and cameras.

Cameras and police are ok ideas but remember he’s got all day to  damage stuff around your property.