Your team needs a chance to get their needs fulfilled too.
Managing a team of software developers (or any team of smart, motivated individuals, for that matter) can be a tricky business. There is pressure coming from the top down to produce results. You aren't getting paid for nothing! However, if you are fortunate enough to be allowed to have direct reports, you now have a little "army" of resources at your disposal to help get it done. It should be as simple as splitting up the work, and letting everyone get at it, right?
In a lot of ways, your one on one meetings with your reports is like your "sprint planning" sessions in an agile methodology. They provide a "rhythm" meeting that your reports can rely on as a chance to get some of your time.
Rhythm meetings should have a rhythm.
When trying to determine how often to have one on one meetings, it's important to keep them predictable and recurring. For the employee, it's important to know that you'll carve out time for their needs on a regular basis. It allows them to plan out the topics (see below) and be sure that the things that are important to them will get dealt with. Keeping to the schedule helps to enhance the trust necessary between the manager and report. Cancelling at the last minute doesn't.
At the very least, if there is some true emergency that makes it impossible to keep the meeting at the normal time, reschedule it for as soon as possible after the missed meeting. Do not cancel it without rescheduling. Fit it back in before the next meeting if at all possible, and get back on schedule. Rhythm meetings are supposed to be rhythmic and predictable. Trust me when I tell you, once you cancel one of these, it becomes all too easy to just do them "whenever", and the value of predictability and the trust of the employee that it is important is lost.
As to how often is appropriate, I'd suggest once per week if at all possible for direct reports, and once every 2-4 weeks for skip level reports (that is, the reports under your reports). If you manage even deeper than that, it would be great to give one on one access to you every few months if at all possible, but that may not be feasible. You really need to look at the number of reports you have in order to figure this out, but it's not unreasonable to expect at least 10% of your time, and maybe even 20% of your time should be available for direct one on one interaction with your reports. While it may seem like a lot, even if you have 8 direct reports, spending 30 minutes with each one once a week is only 4 hours (or 10%) of a "typical" 40 hour week.
It's not you, it's me. No, actually, it's you.
One of the first mistakes that new (or maybe not so new) managers make when starting one on one meetings with their reports is making it about their needs, and not the employee's. If the one on one meeting is nothing more than the manager asking the employee for status on their project, then the meeting is a failure from the start. That sort of status gathering should be handled by your daily stand-ups. If they aren't, you aren't doing it right. The point of a one on one meeting should be to allow your reports to bring their concerns to you, and handle issues that they want prioritized. It's not about you, or your needs, it's about theirs. However, in order to make that work, there's a little catch. You don't (and can't) own the agenda. They do.
What's the story?
We all know that all meetings need an agenda, right? (If you ever go to a meeting and are told "there's no set agenda", feel free to get up and leave. You can tell them I said so.) The employee's rhythm meeting is no exception. The difference here, you go getter, can do sort of person is that this time the agenda isn't yours, it's the employees. They need to know what they want to cover, same as any other meeting. If they don't bring an agenda, you get to get up and leave as well (which is a little awkward if you do the meetings in your office, but they'll get the point more quickly that way too).
To warm them up to the concept, I typically introduce the concept of one on one meetings with my reports using a meeting invitation that says something like this:
Dear <Employee Name>,
This is an invitation to a weekly one on one meeting between you and me. This is an important meeting, and a chance for you to get uninterrupted attention from me. As for the topics we'll discuss - that's for you to decide. This is your meeting. We can talk about whatever you'd like.
That said, this meeting, like all meetings, should have an agenda. We should decide, at the outset of each meeting (or even before that - I love getting agendas before I even show up to meetings) what we will be talking about. This is a critical step to a successful one on one. If you don't have an agenda, we'll just end the meeting early.
Ok, maybe the first time we can stare at each other for 30 minutes, but I will resist setting the topics for you. Additionally, if you catch me changing the topics to things that suit my needs (like asking you for status when that wasn't one of your topics), you can tell me to knock it off.
I look forward to hearing what's on your mind.
Mission accomplished. You've scheduled a regular rhythm meeting, so that even if you don't get a chance to get some feedback from your team during your regular MBWAs, you'll be sure that issues don't stew too long. Additionally, you've set the tone that the meeting is important, and is about the employee.