What records do I need to keep for my tax return?

You should keep records of all business income and expenses (invoices, receipts, bank statements), plus details of any other income like employment, savings interest or property. For a sole trader, HMRC generally expects you to keep these records for at least 5 years after the 31 January submission deadline for that tax year. Digital copies are fine as long as they're legible and complete, and keeping organised records throughout the year makes filing far less stressful.