How do I calculate expenses that aren’t a fixed monthly amount?
Certain expenses are trickier to calculate when they are not regular, such as an annual once-off expense like renewing a TV licence or a constantly changing expense with a wide range from cheap to expensive like medical expenses. Once-off annual expenses are easy, as you only need to take the total amount you are required to pay for the year and divide it by 12 to get the monthly amount. Irregular expenses like medical expenses which are affected by use can be best calculated according to the total expenses for the previous 12 months divided by 12 to get an average expected monthly expense. If there is an expected increase (eg. recent medical diagnosis that will now require frequent medication etc.) then you can include the expected monthly cost of this based on the available information. This inclusion can then be justified to a court if disputed by the other person.