A flexible mortgage is one where you can vary the payments you make from month to month. For example, if your income is changeable, if you receive bonuses regularly, if some months you have a higher expenditure, you can choose to pay less or more to your mortgage. With other mortgages, you can incur a charge for this. A flexible mortgage is more suitable for some people; however, the mortgage lender will have a minimum payment arrangement is adhered to.