Good debt is usually referred to as “tax deductible debt”, and bad debt is referred to as “non-tax deductible debt”.
Some examples of bad debt is: the mortgage on your own home (if you're not claiming any tax deduction on it) or personal loans/credit cards for personal expenses, that sort of thing.
Good debt is: investment property debt, business debt, that sort of stuff, where we can claim it.
If set up right, usually when you go and get a mortgage the bank will give you a 30-year loan and you've got 30 years to pay it off, principal and interest. But if you leverage and set up a debt recycling strategy (this is Stevie and I's example) we can take a 30-year loan, and if set up right, we can pay off our own home in 8.4 years.
So it's a fraction of the time by setting it up correctly.