If you're interested in finding out how long two people have been friends, you may try the following approaches:
Scrolling through their Timelines: You can individually visit the Timelines of both users and scroll back to the earliest posts or interactions they had with each other to get an approximate idea of when their friendship began.
Old Messages: If you are friends with both individuals and they have exchanged messages on Facebook, you can check your own message history with each person and try to find the earliest conversations involving both of them.
Mutual Friends: Reach out to mutual friends and inquire if they happen to know when the two individuals became friends. However, keep in mind that not everyone may remember or be willing to disclose this information.
Third-party Apps and Extensions: Some third-party apps or browser extensions claim to provide additional features for Facebook, but be cautious when using such tools, as they might violate Facebook's terms of service or compromise your account security.
Remember that Facebook's privacy settings and policies may prevent access to certain information, and the platform's features are subject to change over time. Always respect the privacy of others and avoid attempting to access information that is not publicly available or not explicitly shared with you.