what is considered fairly safe in terms of debt to equity ratios on a portfolio?

[Tyler Zindars]

So I have a growing portfolio of rental properties. I wanted to know what the bp community things is a safe range for leveraging rental properties in terms of debt to equity coverage on investment properties? I was thinking that staying within a 60-70% equity position on my rental properties was too conservative? Should I leverage more capital to grow my business? With commercial interest rates at 5% does it make sense to increase my leverage by refinancing some properties and trying to lock in longer term loan rates on my investment properties? I have a long term buy and hold approach to investing. I have been buying distressed single family homes, rehabbing them, and then charging above market rents and renting them out for the long term. Any thoughts?