Compare the AER, not just the headline interest rate, and check whether it is fixed, variable or dependent on a limited-time bonus. Look at access rules, withdrawal limits, minimum deposits, account fees and whether you must hold another product with the provider. Check how your interest will be taxed, including your Personal Savings Allowance, and whether eligible deposits are protected by the FSCS. For fixed-term or notice accounts, make sure the commitment suits your plans and review the provider’s terms before applying.