So much material in this thread. 

A lot of the cost comes in on the finishing material and the type of products you use.  

I also like the control over my materials so that I feel confident that my material is 100% different than other letters that are hitting property owners' mailboxes.

I prefer to keep as much of it electronically as possible.Yes, there are some receipts that I do not bother scanning, but for the most part it is paid via check or credit card which feeds into Quickbooks.All HUD-1s, agreements etc are stored electronically.Files are backed up in the cloud and on an external drive.

There is a lot of expensive materials and classes/seminars you can attend regarding the note business.

I know if you "materially participate" in managing the short-term rental, you can use passive losses against active income for that property, but what about other long-term rentals?

Maintenance is on us in MF for the common areas (weeding, trimming, external lighting, hallway cleanliness, carpet cleaning, salting sidewalks, etc.), whereas in SFH I just let my tenants take care of all of that.

I did all the work myself $1,200 in materials (I also re-wired the entire home & outbuildings, that minor I took in Elect Eng paid off).

How do you store all the installation materials that come with everything you buy for your properties?

i agree with you, I would remove them before cement boarding.it would give you a chance to see the real condition of the existing sub-floor for one, and it would raise the new floor slighter higher than it would need to be if the old material was left there.