How often should one evaluate a plan for an academic career? I'm about to start my PhD. I feel I should try to plan my academic career; or set some general goals at least. The time line could be something like 5-15 years. The first years are easy to plan: study this, study that, publish a few papers etc. It gets more difficult to make plans beyond receiving the PhD. I think that if I don't know where I want to go with my degree, it becomes difficult to make decisions during the coming years: when to say yes, and when to say no. I know I don't want to just end up somewhere doing what other people think I should be doing.

How do you plan your career? How frequently do you update your plan and/or check have you progressed as you planned?
What I tell my students starting out is to make sure that they have realizable goals. Saying "I want to be a postdoc in field X in five years" is realizable. Saying "I want to work for Professor X at University Y on project Z in five years" is probably not realizable. Making sure you have a plausible goal in mind, and the ability to work toward it is incredibly important.

However, it's important to realize that goals and opportunities change over time. What you think you want to do now may not be what you want to do a year from now. So that's why it's important not to have goals that are too narrowly defined—otherwise, it makes it harder to change your mind later and still be satisfied with the way things turn out.

How often do you reassess goals? As often as you feel you need to. But you should also distinguish between the different ranges of priorities—short-range, mid-range, and long-range.  Short- and mid-range should be reviewed on a very regular basis (weekly to monthly); the longer-range stuff at least a few times a year. But these are guidelines that work for me; you need to find a system that works for you.