Some people over-emphasize this. Generally speaking, 10k in debt, 10k in the bank, at a non-usurious interest rate is far more stable than 0 in debt and $3.50 in the bank.
I'd contend that debts south of 5% fixed interest rate should be HIGHLY considered as "not worth paying down" until your retirement account is fully loaded with enough cash to retire TODAY as this is a very strangely low rate, and one that will be over the life of most loans in that tier, at or less than inflation (looking at historical levels of inflation)
You're not going to be able to borrow at 4% when inflation is at 5%, but you sure can keep on to that 4% debt from now for 10 years, and instead bank extra payments or invest them