If its the same dated filter I installed at move out I'll charge the tenant for a service of the unit due to the added strain on the system they caused by not following our lease agreement.With your plumbing situation I would include a lease provision that states tenants are responsible for maintaining all plumbing, excluding root intrusion and the like.

You can get the stats from the  CDC here:https://www.cdc.gov/flu/about/...The CDC flu estimates for the 2019-2020 flu season between October 1st 2019 through Feb 15, 2020 looks like this:29 - 41 million flu illnesses13 - 19 million flu medical visits280k-500k flu hospitalizations16k-41k flu deathsSo that is 16,000 - 41,000 flu deaths in just the USA in 4.5 months.These stats fluctuate every year depending on how bad the flu strains are in any given year.  

If you can't afford to have 20k-30k in a true "rehab" budget for this, I think you'll find you are fronting a high CAPEX bill up front with no/little income coming in, and that can be a major strain if you aren't expecting it.

My concerns would be:-the potential for strained relations within the family-owning a big (and probably old?)

@Rawn Wilson You have every right to pursue litigation and you should, so long as it does not cause you financial strain. 

I hadn't actually drained a lithium ion battery until yesterday (If I'm coming down a ladder or switching tools, I'm rotating batteries so I don't get stuck mid task).

I get around the "more than half the services" rule by two means: (1) I work a rotational schedule for my W2 job where I work 4 weeks offshore on a rig, then get 4 weeks off.

You chose to manage on your own to save 10% a year which sounds like a smart choice...until feces hits the rotating oscillator.

I keep 3 full propane bottles on hand so we can rotate them as needed.

When that tenants leaves, the Landlord finds a new tenant and feces hits the rotating oscillator because they are over-confident and ill-prepared.