As a consultant, I work with multiple Salesforce orgs.
Some of them are mine, some are my clients. I use Bitwarden as a password manager to manage login credentials, including passkeys.
I never felt the need to track more details about these orgs.
However every once in a while, Salesforce sends an email stating that for a list of Org Ids, a feature will be deprecated soon.
It looks like this:

This type of email never really concerned me, as a solution would present itself when the time came.
But as time goes on, I’m realizing there’s an advantage to tracking Org Ids in a safe location. Not only for these types of emails, but also when Salesforce immediately blocks me from logging in because I accidentally used a VPN.
The takeaway
Consider tracking the Ids of the orgs you manage. Setup > Company Information > Salesforce.com Organization ID