I think defining vision/mission it's very important if you do it seriously, as in seriously start thinking about what your company is, what it stands for, what it wants to achieve and how it wants to get there.
The value is not _strictly_ in the statement themselves, but in the process that came to define them and in how you implement the "how to get there".
I would reccomend everybody to read HBRs 10 Must Read on Business Strategy (http://amzn.to/wuvIoW), a small book that seriously makes you think why some companies fail and some make it.
There's a full chapter on mission/vision and I think it's your best answer on how to approach the whole process.
The value is not _strictly_ in the statement themselves, but in the process that came to define them and in how you implement the "how to get there".
I would reccomend everybody to read HBRs 10 Must Read on Business Strategy (http://amzn.to/wuvIoW), a small book that seriously makes you think why some companies fail and some make it.
There's a full chapter on mission/vision and I think it's your best answer on how to approach the whole process.