Basic guidelines In this series, I examine inventory using a simple rule of thumb: Inventory increases ought to roughly parallel revenue increases. If inventory bloats more quickly than sales grow, this might be a sign that expected sales haven't materialized. Is the current inventory situation at Furmanite (NYSE: FRM) out of line? To figure that out, start by comparing the company's inventory growth to sales growth. How is Furmanite doing by this quick checkup? At first glance, not so great. Trailing-12-month revenue increased 9.1%, and inventory increased 16.0%.