An executive chef asks the same question to all interviewees at his restaurants; “What is the proper way to prepare rice?” The correct answer of course, is “whatever way you want it cooked, all-knowing one.”
While that management style may increase consistency, consider how downright detrimental it can be if used too often or too extensively. Restricted workers create stagnation. Workers become peons, perform the bare minimum, lose motivation, and eventually leave, forcing employers to spend a lot of time replacing them. That’s expensive (and boring).
Staff should be given some freedom to experiment, fail, grow, improve, and if you’re lucky, sometimes innovate! You can see this approach in action at Google, where engineers are allotted one day per week to work on projects that aren’t necessarily in their job descriptions. Low and behold, some of the most successful products at Google started in that sandbox (Gmail, Google News, Orkut, Adsense). That’s profitable (and exciting!).
Also worth considering–inspired people like to talk to other people (who would’ve thunk it?!?) People who love their job will often spread the word about where they work, talk about how great the products are, even recruit others to work there. That’s good marketing.