How often does Google issue Android security patches?

Google issues Android security patches monthly, typically around the first Monday of each month, which corresponds to "every 30 days." This regular schedule ensures that newly discovered vulnerabilities are addressed promptly, maintaining the security of Android devices. "Every 90 days" would mean patches are released quarterly, which is too infrequent for critical security updates. "Every 7 days" (weekly) would be too aggressive and resource-intensive for both Google and device manufacturers to consistently implement and test. "Once a year" is far too infrequent and would leave devices exposed to known vulnerabilities for extended periods.