> A debtor's promise of future payments is worth less than an immediate payment of the same total amount because the creditor cannot use the money right away, inflation may cause the value of the dollar to decline before the debtor pays, and there is always some risk of nonpayment. The challenge for bankruptcy courts reviewing such repayment schemes, therefore, is to choose an interest rate sufficient to compensate the creditor for these concerns.

Till v. SCS Credit Corp, 541 US 465, 474 (2004).