An account may still list old phones, browsers, and applications as signed in. Periodic review helps identify access that is no longer needed. One entry does not always represent one physical device: several sessions can belong to the same computer. Inspect the details and context before assuming an unfamiliar label automatically indicates an attack.
Open the official overview
Open security settings through the service's known website or app rather than an unexpected alert link. Confirm which account is open; similar personal and work addresses are easy to confuse. The overview must belong to the account you intend to review.
Compare device name, browser, recent activity, and any reported location with your own use. A generic device label may represent a familiar phone. Conversely, a familiar-sounding name alone is not proof. Record unclear details before making changes.
Distinguish sessions from devices
Google describes a session as a period of sign-in through a browser, app, or service. One device can therefore have several sessions. Ending that device's access may require signing out every associated session. Read the service's explanation rather than assuming a universal effect from one button.
A historical entry may remain visible after sign-out. Check its reported status. The device overview is also not necessarily a complete list of connected third-party applications. Those permissions are often managed separately and deserve review during a broader access check.
An old phone before handover
A retired phone may have been signed into several accounts. Review important email, storage, and work services as well as the central device-provider account. Some applications manage their sessions independently. Signing out in one place is therefore not proof that all other access has been removed.
Keep the device available until the handover process is complete when it still belongs to you and is accessible. Test the new sign-in route before removing old factors. Then follow the intended process for clearing the phone's data. Account review and device reset complement each other because they address different parts of its previous use.
Remove access no longer needed
Sign out old or unused devices through the intended controls. First ensure that current access and recovery options remain available. For unfamiliar activity, also follow the official account-protection process; removing an entry alone does not explain its cause.
Review again after selling a device or having one repaired. Signing out does not automatically erase everything already stored locally on another device. That requires a separate appropriate cleanup process. Where supported, give devices recognizable names to make future reviews easier.
Keep a small inventory of devices you still own and update it after replacements. This makes the next review easier and helps distinguish old personal hardware from an unexplained active session.