Not as much testing of the materials but more of quality and compliance.

He can take that 150K and turn it into $2.5 - $3 million (conservatively) in 40 years without literally lifting a finger...just put it in your everyday quality funds in the market and be done with it. 

Quality of property, size, age, design, amenities, distance to attractions, and reviews all play a part. 

Premium Quality.

I personally hate them because they are cheap construction quality, cheap products used and limited on size and layout. 

There's a lot that really should go on around it, but that's the core of it.That's enough to make you very dangerous because I don't have the time / room here to give you the content of the five or so 8-hour classes where that instruction is contained (Tax and Legal I & II, Self Directed Retirement Accounts, Private + Hard Money, Property Analysis).Again, spend some quality time here on BP.

Why not buy a quality washer and dryer for the duplex and in the future you can up your rent.

Just remember, there will always be deals - don't sacrifice quality and preparedness to satisfy enthusiasm!

Tenet pays $875/month and is inline with the market based on quality/location. 

There are three other factor, both very controllable, that also slow or eliminate depreciation:The quality and/or size of the home in the first place;High quality homes use better materials which last longer and look better longer thus increasing the probability the home will hold value.Homes smaller than 16'x80' normally depreciate faster than larger homes because small homes are truly out of fashion (forgive me tiny home advocates) and because smaller manufactured homes look more like "trailers" than a home.The way the land lease community is operated.Well run communities looking to protect the long-term investment of the community over short-term gains almost always stem or slow home depreciation.