An expense can feel sudden even when its due date is predictable. Listing future bills makes it easier to see how much time you have to prepare.
Choose an expense such as annual software or a maintenance bill. Write down the estimated amount and months remaining until it is due. For a 240-unit expense due in six months, the arithmetic works out to 40 units per month if you start from zero.
Keep that amount visible in your monthly plan alongside everyday bills. Update the estimate when you get a new quote or the due date moves. This approach works for known costs with a reasonable estimate.
Further reading: CFPB Your Money, Your Goals worksheets.