With the lid closed, it looks cleaner, sanitary,  and protects the plumbing--why would a person not close the lid? 

There is nothing in the lease that pertains particularly to rodents, etc. but only states to keep the property "clean and sanitary".

Your unit should have some sort of laminate floors, ceramic tile and there is some beautiful rubber-type flooring that looks like laminate flooring and this stuff is beautiful and looks like it is indestructable.You have to clean the stove, refrigerator ant bathtub in every unit even when the tenants leave your unit looking spotless because you can't expect your tenants to leave a unit clean and sanitary like a professional cleaning service does.As I just wrote in a recent post, when I sold my 20 properties in Las Vegas last year my wife spent as much as two days cleaning one stove (JUST THE STOVE) and the stove was still filthy.

In regard to common expenses of a rental, these are negotiable between the Tenant and Landlord, whether written on a napkin like in the old days or by using a more formal legal looking form, as long as there is a meeting of the minds and the document is fully executed without duress, you have a bonafide contract.

An older building may have growing infrastructure maintenance and replacement needs for systems such as sanitary sewer lines, water, electric, etc.

If I don't sign a contract on the spot, my approach is to generally work out the details via a napkin (if in person) or via email.  

I want to stress that the 50% rule is a very quick and basic napkin analysis, and would not base your buying decision with this method. 

You can use any type of contract, you can even hand write one on a cocktail napkin. 

Don't do anything on a handshake or napkin agreement. 

@Brandon G.Here is a "back of a napkin analysis":Gross rent: $1395*12 = $16740Less vacancy (8%): effective projected gross rent: $15400Less taxes, insurance, PM (10%), etc. : $15400 - $7164 = $8246Say you financed 100K @4.5%.