There are no rules about when and how often we should do one to ones, but my view is that monthly is best. Why, well let’s take a look at why we do one to ones in the first place.
During the month we may have lots of conversations with our team members about specific projects, or tasks, but these are not the same as a one to one. A one to one is an opportunity for the team member to express how they think they are doing, how the work is going overall, what observations they have. It is also a chance for them to talk about challenges in work, maybe with colleagues, other departments or their manager! These could be difficult conversations and the one to one gives them a format in which to have them.
The one to one is also a time to check in with performance, both of the team member and the manager. It’s an opportunity to make sure the person is on track, or being stretched enough, or getting the support and development they need. The emphasis is not on judgement but on support required.
Above all the one to one is a chance for the team member to be listened to. A chance for them to express their thoughts and views on whatever is important to them. Put that way, once a month is probably a minimum.