Setting up a territory in an effective manner is where sellers often make significant mistakes. In fact, this can mean the difference between a successful sales career and a moderate or less than successful one. As I mentioned,my first company had three outstanding sellers, and their success was a direct result of their having effectively established their respective sales territories. Similarly, some companies severely limit their effectiveness by not establishing and deploying proper sales territories. Not only does this limit their selling success but it also costs millions, and possibly hundreds of millions, of dollars year through duplication of sales efforts.