While the exact frequency can vary depending on the specific security requirements of an organization or the sensitivity of the information being protected, general best practices recommend changing passwords regularly to enhance security. Currently, the consensus among cybersecurity experts is that users should consider changing their passwords at least every 3 to 6 months.
However, if there are indications of a security breach or if a particular account is compromised, users should change their passwords immediately, regardless of when they last changed them. It’s also important to use strong, unique passwords and to enable two-factor authentication whenever possible.
So, based on the options provided, the best recommendation would be at least every six months.