Should I be leveraging property for 30yrs at age 52?

[Robert Blade]

I started investing in sf houses a year and so far I have four properties, one is paid for and the other three are leveraged for 30yrs. I’m 52 should I continue to leverage or pay some off? I’m thinking that I should keep leveraging until I get say like ten houses and use the net income to pay off one at a time but I’m not sure if that’s a good idea. Please help?