Some second mortgage loans may extend for as long as 15 or 20 years; others may require repayment in one year. You will need to discuss the repayment terms with the individual mortgage company and select one that offers terms that best suit your needs. For example, if you need to borrow $20,000 to make repairs on your home, you may not want a loan that requires you to repay the entire amount in one or two years because the monthly payments may be too high.