The frequency of replacing NAS drives depends heavily on usage and expected lifespan. While some manufacturers quote a lifespan of 5-7 years, heavy workloads and continuous use can significantly reduce that lifespan. Regular backups are crucial for data security, regardless of drive lifespan. Monitoring drive health and proactively replacing failing drives is important to prevent data loss. High-performance NAS systems and those with more frequent write operations might require more frequent drive replacements. Ultimately, the best approach is to monitor drive health indicators and replace failing or nearing-failure drives before data is lost.