The second summer even with preventive maintenance and letters to tenants warning them of the breaking the A/C they would break down.My Vacancy rate is 20% over the course of the year, and it costs me 1 month rent to lease someone into a unit and another month when they move out.  

This law prevents any kind of "up-front charge" that is not specifically listed in the statute, even if that fee is deferred to a later point of the Tenant's occupancy (ie, second month).The Effects to Massachusetts Property Managers are:No Application FeeNo Amenity Fee / Amenity Use Fee / Move-In FeeNo Community FeeNo Up-Front Pet FeeMonthly Pet Fees are permitted: "The monthly pet fee is not incurred up front, but rather each month during which the tenant owns a pet.

I was going to replace the carpet and was willing to wave the carpet stains and return her SD in full if she paid the lease in full for November.So if I was to keep the SD - how can I prevent her from suing me for that?

The whole point of the winterization process is to prevent pipes freezing during extreme cold.

Thinking it through in the beginning, and writing it up goes a long way in preventing conflict later on.

A mortgage won't prevent you from buying rentals.  

It would seem that this large debt load/mortgage payment would prevent me from qualifying, and this cash flow detriment would prevent me from even saving enough, to invest in anything else any time soon given my limited capital.  

You might just need to have it augered and/or a backflow preventer installed.

I had planned to attend a local REIA meeting last night but certain circumstances prevented me from being able to attend.

@Joe Villeneuve Good info, how did you educate yourself on the Detroit area well enough to prevent losing a lot of $$$.