I'd like to supplement my income with monthly cash flow from the properties at the same time building equity in all of the homes that I own. 

We eventually paid $60,000 to install a supplemental AC system just for our suite.As a property manager I love it.

I'm looking to supplement my income by building a rental portfolio then eventually replace my income and retire early in 5-6 years.

I should clarify that I already have a retirement plan in place through my "real" job, this would be supplemental.  

She has been an investor in the area for over 20 years and runs a very successful meeting group for investors, we are doing property management together and I am assisting in finding investment properties for her however I also want to supplement my time and income by working with home buyers...I just love it!

Sometimes there will also be supplemental tax bills due during your holding period, so check with the tax collector in your area.

You could sell the 50 units and buy say10 properties-airbnb maybe-and have that supplement your gains from the sale.

I've kicked around the idea of diversifying into short-term rentals (not switching, just adding one or a small handful of properties over time to supplement my regular portfolio). 

Supplement retirement income and help provide income for our 5th child who has Down syndrome.

Plenty of investors have supplemented their rehabs using credit cards and end up fine at the end of the day..