Just thought I'd share my experience of one on ones.
I work in the not for profit sector in the UK and one on ones are commonplace, except we call it supervision and we carry it out fortnightly or monthly depending on the needs of the supervisee and some times the need of the supervisor.
We recognise 3 forms of supervision formal, informal and group.
Formal supervision to me is an essential part of management responsibility, and it aims to maximise effective performance.
Like one on ones supervision is structured and has 4 main functions,management, education & development, support and mediation.
I see supervision as an integral part of every managers or leaders job description and we provide training for those who are new to the concept either as a supervisor or a supervisee. Like one on ones we have frequency, rules for the "setting" we encourage joint agenda and insist on written records.
In addition I find that good supervision makes for easy staff appraisals