I finally came to the point where I decided to take the stress out of the equation.My business model, which has proven to be very successful at retaining long term tenants, is I don't charge late fees.

Should I see invoices or receipts for materials purchased or labor hours utilized?

In title states a lender may be entitled to retain a property, unless a borrower takes other actions for excess equity. 

The property withstood the '89 earthquake, had some damage mainly due to trees, I think, in the'83 storm, and has a pretty decent retaining wall thats tied back well.

Regarding insulation, there are many sound barrier insulation materials out there.

Failing to do something like that may cause evidentiary nightmares for the attorney you will inevitably have to hire when something goes wrong.Note: Not intended to be legal advice or actionable educational material.

I think most people in Tucson use Pioneer landscaping materials for the gravel.My last triplex I did I spent $200 on plants about $400 on gravel and $300 on labor. 

We also include rules about candles, decorative holiday lights, storage of flammable and hazardous materials, smoke and CO detectors, fireworks, portable heaters, extension cords, electrical safety, egress, excessive cluttter and hoarding, and our no-smoking policy. 

It's quite possible that material is simply outdated. 

The following code supports Susan's and my remarks:§ 1.263(a)-1(f)(1)(i) Except as otherwise provided in paragraph (f)(2) of this section, a taxpayer electing to apply the de minimis safe harbor under this paragraph (f) may not capitalize under § 1.263(a)-2(d)(1) or § 1.263(a)-3(d) any amount paid in the taxable year for the acquisition or production of a unit of tangible property nor treat as a material or supply under § 1.162-3(a) any amount paid in the taxable year for tangible property if the amount specified under this paragraph (f)(1) meets the requirements of paragraph (f)(1)(i) or (f)(1)(ii) of this section.