Leverage is why real estate builds wealth faster than most assets — you control a $400,000 property with $100,000 — and it's also why over-extended landlords lose everything in downturns. The same multiplier works in both directions.
The amplification math
Buy a $400,000 property in cash and it appreciates 5%: you made $20,000 on $400,000 — a 5% gain. Buy it with 25% down and the same $20,000 sits on $100,000 of your cash — a 20% gain, before loan costs. Now run it backwards: a 5% price decline is also a 20% loss of your equity. Leverage doesn't change the property; it changes your exposure to it.
The cash-flow squeeze
More debt means higher payments, and higher payments eat the cushion between NOI and the mortgage. At 80% loan-to-value many rentals barely break even monthly; at 60% the same building throws off comfortable cash flow. Thin cash flow plus one long vacancy is how properties with "great equity" end up in forced sales — equity doesn't pay the mortgage, cash does.
Finding your level
A common posture for small investors: 65–75% loan-to-value at acquisition, DSCR of at least 1.25 on real numbers, and reserves of 3–6 months of expenses per property. Borrowing more against your equity is a good idea only when rents strongly cover the new debt and you have deep reserves; it rarely makes sense just because a lender will allow it.
Worked example
Two investors buy identical $300,000 duplexes with $24,000 NOI. Investor A puts 40% down ($120,000); annual debt service is about $13,700; cash flow $10,300. Investor B puts 20% down ($60,000); debt service about $18,200; cash flow $5,800. A 10% rent decline plus a vacancy cuts $6,000 of NOI: A still clears $4,300; B goes slightly negative and must feed the property.
When this rule of thumb breaks
Conservative leverage isn't free — idle equity has an opportunity cost, and in inflationary periods fixed-rate debt quietly works in your favor. Very low leverage on a growing portfolio can mean you bought one property when the same cash safely supported two. The trade-off is real on both sides: match leverage to your reserves and income stability, and ask a lender to stress-test the numbers with you before assuming the maximum.