Supervising a graduate student is one of the most rewarding activities of a faculty member. Supervising a post-doc is a treat, a privilege, and a responsibility.
There are two types of post-doc, and it is important to distinguish them. There are those who have their own funding and their own project. You are the supervisor and your job depends on what the post-doc expects from you. At a minimum, you will provide comments on first drafts of papers. At a maximum, you will be asked to comment on the design of the study, the methodological choices to be made, the preliminary findings, the framing of the paper, and the many different drafts, plus suggestions about where to present and submit, and advice when the (alas often) reject decision comes in. In some cases, you will become a co-author. This is easy and fun. The collaboration can be intense and stimulating, or relaxed but still quite interesting.
The second type of post-doc is the one that you are funding yourself (or your team or research centre). This is a post-doc that you have chosen after some selection process. If (like me!) you have good judgment, then you have an extremely clever and dynamic young researcher who will be working with you, and this is awesome…There is one disadvantage. The post-doc position entails some duties that the post-doc will need to fulfill and that may not be the most stimulating for the post-doc and that will take time away from writing and publishing, which are the most important things that the post-doc needs to do to be competitive on the market and get a tenure track job.
You are paying the post-doc and this means that the post-doc needs to perform a number of tasks for you (or the team or the research centre). This needs to be said clearly. Ideally, the tasks that need to be performed should be laid out precisely but my experience is that it is very difficult to anticipate these tasks with any detail, which is no excuse for not trying to be as explicit as possible. What I have found useful is to tell the post-doc how much time she will have to devote to her own research, collaborative research, and all kinds of administrative duties. This is also tough to estimate but this makes the point that you expect the post-doc to do several things, whether she likes it or not, but also to leave her time to advance her own research and career profile.
Supervising a post-doc is a treat and a privilege. This provides you with a golden opportunity to collaborate with someone who is probably brighter than you, and more up to date with the recent literature and methodology, but who still has a few things to learn from you about how social science works. There is no free ride and this entails responsibilities. You want the post-doc to succeed in her career and you need to make sure that the tasks she needs to perform does not prevent her from being successful. Enjoy the experience. It is fun. I strongly recommend it.
One final word. Short-term (less than two years) post-docs are a challenge. As soon as the person arrives, she needs to think about applying to new positions and it is much more difficult for the post-doc to fully integrate into the new research environment.