Make sure the reasons why you're planning to leave are clear to yourself.

"At your job, there are curable problems -- like not being paid enough and needing more vacation time, both of which are negotiable," says Tim Ferriss, author of "The 4-Hour Workweek."

"Don't quit in a feeble effort to get to greener pastures."

As to incurable problems that necessitate leaving: "Your boss is a permanent dick," says Ferriss. "Or you're dealing with an existential, soul-crushing dilemma at work."