If the answer is yes, then it's a no brainer to make minimum payments on your 2.8% interest rate mortgage, and use the funds that you would have paid extra to pay it down faster, to either invest in more real estate, the market, or anywhere else where you can get a ROI > 2.8%.If the answer is no, then feel free to aggressively pay it down as fast as possible, to become debt-free faster, and just have a large amount of money in savings or to splurge with.The bottom line is that your 2.8% mortgage is GOOD debt.

I have 30+ units and on a regular month usually only spend about 5 hours total on management things, most of which involves collecting rents and bookkeeping.

t happens, and it usually happens when one least expects it. 

It's easy to obtain, costs very little, and doesn't require extra, on-going effort to maintain.

In addition, I presented his was not the usual use case because he was unleveraged.  

Go to Etsy and search for "rental property tracker," and you will find hundreds of nice spreadsheets to track 10-20 rentals, usually for under $10.Software has extremely helpful features like online payments, marketing syndication (click a button, and your property is advertised on multiple sites), electronic document review/signing, maintenance tracking, and owner reports.

With some more math, you’ll see that the extra amount in dollars is not that much compared to the total amount of interest paid.

This is interesting and I look forward to the feedback.But, I don't know if I want extra buoyancy in a hot tub?

It was the best solution but it did cost extra. 

Most investors don’t even need an LLC and a holding company is extra, extra overkill though IMO.