Inventory planners are responsible for the making sure that the company's stores are stocked with the appropriate products. At first glance, this may not seem too demanding, but consider that many major retailers operate thousands of stores, and that these stores may carry different product mixes because of the customers they serve. Then, consider that retailers stock different products for different seasons and promotions -- think about all of the "Back to School" promotions and holiday products you see at a major retailer. At many retailers, the inventory planning department is also responsible for making sure that the actual "Back to School" signs and product displays are shipped to the stores.

Inventory planning roles are very quantitative and detail-oriented. Professionals in these must learn inventory tracking systems and software that their companies have developed or purchased. Planners generally work out of the company's corporate headquarters or major offices.

While planners are responsible for making sure that the stores are stocked, buyers are responsible for deciding what products the stores should sell. Faced with a surplus of companies all making the case that their products will be the next big thing, buyers must judiciously choose the products they believe will "sell through" to customers.

How do buyers decide? They stay on top of trends, talk with professionals in their industry to try to pick up on any "buzz" surrounding a particular product, evaluate the products' quality and appeal themselves. Then, combining all of this knowledge and the knowledge of who their store's customers are (and what they are willing to pay for certain types of items), the buyers make decisions on what products to stock. Unlike planners, buyers travel a great deal in order to meet with vendors.

Both buyers and planners are organized by the category of product they focus on: think "sporting goods" or "toddler toys" or "women's casual shoes." Inventory planning roles can be entry-level positions, while buying jobs generally require a few years' experience in retail (usually in a planning role).