A leverage ratio says how much debt there is; the maturity ladder says when it becomes a problem. A company at 3 times net-debt-to-ebitda with nothing due for six years is in a different position from one at 2 times with everything due next year.
Refinancing risk is usually visible well ahead of time, because the maturity schedule is disclosed. The market often reprices the equity long before the actual maturity, as the refinancing terms become predictable.
Example: Northwind Tools has $60M due next year and nothing else until 2029. If its 4.1% notes had to be refinanced today at 7.5%, annual interest-expense would rise by roughly $8.5M, about 11% of net income.
Related: long-term-debt, short-term-debt, interest-coverage-ratio, covenant, net-debt-to-ebitda