Maintaining ISO 27001 certification requires ongoing effort. Businesses need to continually monitor and improve their information security management system (ISMS), ensuring it remains effective in the face of changing threats and business needs. This includes regularly reviewing and updating security policies, conducting internal audits, and addressing any identified non-conformities. Additionally, businesses must undergo surveillance audits by an external certification body at least once a year to verify their continued compliance with ISO 27001 requirements.