When creating new Flows for my company, should I be using a sepecial developer ID, or should I be using my own. My concern is that if I leave the company, and they remove my ID, then the flows we worked so hard on would stop working.
Ultimately the account that creates the flows isn't very important. If the user who creates the flow leaves the company, the flows stick around and continue running.
Of course any connections that are used by flows are subject to be revoked potentially if the creators leave the company. At such a time other owners of the flow could then add their own connections to the flow so that it could continue running. Ideally this transition would happen before the user leaves the company so that the flows could continue running uninterupted.
In the event a user forgets or declines to share a flow with another owner before leaving the company, tenant admins can still manage the flow in the admin portal. There they can assign new owners to take up administration of users' flows.