Obviously this is dependent on your local area, saturation and quality of product.

@Jane DangThe short answer is: 27.5 yr depreciation.The long answer is: the line you are asking about, the one between repairs and improvements, does not exist.

I have purchased existing MH loans in the past.

What would be my reason to the existing tenants for putting thier live-in child on the lease (cat asside)?  

Think about buying another home for yourself that you can fix up like you did to your current home and rent out your existing property!

A house has come up for sale next door to one of their existing houses, and due to the convenience that would provide from an operational standpoint, they want to open up shop there.  

The first few times were far enough apart from each other that we searched for other simple reasons it would not work only to be told we have to re-setup the existing tenant in payments. 

And since most people have mortgages, and the sale is "subject to" existing liens you need to be very cautious. 

For a tenant to receive a reduction, the landlord must have actual or constructive notice of the existence of the defective condition."

Is building a new property for a house hack potentially a good idea if our goal is to continue to scale/grow our capital or should we just stick to looking at existing properties that need work and pull our money out post-renovation?