To pay off rental properties or not...that is the question!

[Brandon Luke]

I am developing my business plan for buying and holding. I was talking out some ideas with another investor, and she said you should never pay off your properties, and never pay all cash. It seems to me that if you don't have a mortgage to pay that your profit would would be a lot greater. And you would be less likely to over leverage yourself. Am I missing something? What are the pros and cons? Am I missing something?