At my own home I do early routine cleaning and maintenance which runs about 100$ a year, so wondering if this can be done every 6 months or every year to clean the drain pan, filter, etc. at what frequency? 

@Joshua FerrariHow well do you clean your property before tenant moves in?

If you want to chase down probate leads, you've got some homework to do first, like the probate laws for your area and how someone can navigate the process (your counties website should have some guides for this), how to find good estate sale reps, how to do clean outs for cheap, vendor lists, etc.. all the things someone that is overwhelmed with the role that has been thrust upon them and how to best help them.

I’ve only been advised to make sure the funds are cleanly separated

If the tank, assuming it is oil, was not fully washed out and cleaned, the sand presses into the oil and the oil will break the bottom of the tank and hit the soil below.

It was a big project and above all did a great job and cleaned up afterwards.

What they might charge thousands for you might can pick up for 100 bucks with someone cleaning out their closet.

I would really appreciate to get some feedback about how extensive your cleaning procedures are when you are doing a turnover.

It's a very equitable way to structure the deal and especially if you're co-investing a significant amount you can keep a lot of the deal yourself, and complete control so it's very clean.

A very common scenario for a new(er) investor: Tenant fails to pay rent, leaves the home with $2,000 in cleaning and repairs, and it takes you a month to turn the property around and get it filled.