How much leverage is too much leverage?

[Clark Bown]

Just this month my wife and I closed on our first home and rental property. We plan to house hack by renting the bottom unit while living in the top. We’ll be doing some rehab to the bottom and hope to have renters in by January.

The whole process is very exciting and if all goes well with this rental, while we’re young, we plan to house hack a new property every year while holding and renting the other properties for a steady cash flow.

Since the property is considered a primary residence, our lender allows only 3.5% down payment. I've considered the BRRR method but am concerned with the major amounts of debt acquired if we refinance over and over again in different properties. I know debt to income ratios depend a lot on personal comfort level, but I'd like to see what everyone else thinks about this. How much leverage is too much leverage? I know some big time real estate investors that have over $20 million in debt. What amounts are you comfortable with?