When is a good time to go visiting potential post-doc opportunities? I am in my last year of graduate studies. I have lately started networking for post-doc opportunities with some of the prominent people out there. I believe I have done a decent job in presenting myself so far, and I have gotten some people interested in discussing it further. The typical scenario would be to initiate formal contact by email then, if both parties are interested, pay a visit to the lab and talk with the people working there. 

Now that I am starting to plan these things, I am wondering if the timing is optimal and if not how I should be putting them. I like planning these things in advance and not having to end up stressing about it all the way in the end. Heaving a big margin also provides time for project planning, as well as finding and applying for post-doc grants. 

On the down-side, this last year is all I got to finish my projects, get papers out and also write a good thesis. All of which, I am sure, will take a significant amount of time. Ideally worrying/planning about the next step, should not prevent me from progressing as efficiently as I can. 

So, in general, when would be a good time to take active and serious steps towards the next employment after graduate studies?
The answer depends on your geographical and academic areas. 


Postdoctoral positions in Europe are often attached to specific research groups and are funded through grants obtained by the head of laboratory/research group. As such their availability are often announced after the successful grant application, which means sometimes in the spring in general. On the other hand, if you have a specific person you want to work with and you have discussed this, it is good to get started early so you can help out as much as reasonable with the grant application process. (This is assuming that you have struck a mutual agreement that she will hire you if the grant is successful.)
Postdoctoral positions in the United States and Canada are, depending on field, are sometimes funded as in the European case described above, and sometimes funded by the department (departmental, "named" postdoctoral positions). In the latter case the application process may have begun already and you should consult the appropriate trade magazines or bulletin boards to keep yourself posted of these opportunities. (I see that your profile indicates an applied math background; many math positions are posted on MathJobs and AcademicJobsOnline, and you should of course keep an eye on SIAM publications.)

In fact, the schedule is also similar for faculty positions in the United States: you generally expect to be applying during the fall and winter (and sometimes the summer) of the year prior to the start date. (Something you should keep in mind after you land your postdoc job.)
The various countries' equivalents of the National Science Foundation also offer postdoc funding opportunities with varying deadlines. For example, the United State NSF funds postdoctoral research in various fields. And you are likely already too late: the Mathematics deadline was last week. While the Swiss NSF has a postdoct program whose due date is not under February next year.