Payments on account can add a large chunk onto the amount of tax that you have to pay. If your income is likely to be lower next year than this year then it may be worth reducing your payments on account and we sometimes do this for clients who are winding up their sole trader business or who are going through a hard time. But BEWARE! If you reduce your payments too low and the final tax bill comes out higher then you will have to pay interest on the shortfall. This is to discourage people from reducing their payments too far.