You need to make Payments on Account if your Self Assessment tax bill for the year is more than £1,000, and less than 80% of that tax was collected at source through PAYE. This typically applies to self-employed people, landlords, company directors, and anyone else with significant income that is not taxed automatically through payroll. If this is your first year of Self Assessment and your bill exceeds £1,000, you will need to make your first Payment on Account at the same time as you pay your tax bill, on 31 January. If your income drops significantly, you can ask HMRC to reduce your payments on account to avoid overpaying.
