But, they have ZERO liability for the performance of that tenant.Second, 97%+ have no idea on how to screen a tenant, other than income = 3x rent and a credit score.

Tapping into that equity through a HELOC or cash-out refinance and reinvesting in higher-performing assets could improve their ROI significantly.

Never heard of him.Make sure you perform proper due diligence.

The return on equity is probably very low considering they are paid off so maybe explore refinancing or selling the lowest performing one(s) or your biggest headaches to reinvest in more lucrative deals.I noticed you also used a metric of number of rentals to attain your goal rather than $$$/month.

The only real, dependable income comes from a property that is a lot of work (well performing short term rental), one that is paid off, or one that you have owned for a long time to see rent appreciation. 

@Randall King If you find the property isn't performing well, a 1031 exchange would defer the tax and concentrate that equity into something that has a greater cash flow potential, like what @Corby Goade said.

I’ve invested relatively small amounts in “flyers”, and because the invested amount was small in relation to my overall portfolio chose not to perform a thorough due diligence.  

Always perform thorough market research and verify the numbers on any property you consider.

I think what you describe is pretty much standard performance for rental properties if your not paying cash and I am just assuming your putting max debt on them to try to get your return numbers into your criteria..

Aaron I would not pay but if they wanted to have this added I would have a licensed electrician perform the work.