Pay off properties or leverage and buy more?

[Account Closed]

What is everyone's consensus on paying off rental properties vs leveraging to aquire more? I understand from an appreciation standpoint it definitely makes more sense to be leveraged, I also understand that my return on equity will probably be abysmally low if it's sitting in a paid off rental. 

However from a risk standpoint, would it be a good idea to maybe have one paid off for every 3 I have leveraged? I'm worried that if I buy at the top I'll be over-leveraged and not be able to absorb a drop in the market. 

Please give me your thoughts, thank you.