Mortgage contracts that require borrowers to make fixed payments each month have been around for a long time. These contracts can become less affordable if interest rates go up, leading to payment imbalances. Some new mortgage designs have been suggested to solve this problem, but they come with their own risks. Shortening the time it takes to pay off a mortgage can save money in the long run, while longer repayment periods can make monthly payments more manageable. Flexible mortgages offer even more options for saving on interest or lowering payments. Traditional mortgages are easy to understand for borrowers and provide a steady income for lenders. Policymakers have to weigh the pros and cons of these contracts, like reducing tax benefits but dealing with payment imbalances.