There are two reasons to purchase and use heavy duty office chairs. One is that some people are simply too stout for a basic light duty chair. As such they need wider seats, stiffer backs and in many cases higher grade hydraulic cushioning, When an overweight person continually uses a conventional weight light duty chair, the hydraulic seat height adjustment will collapse in just a few months. And once that device is broken it cannot be cost effectively repaired and the entire chair must be replaced.
Very often companies find themselves replacing standard duty office chairs used by heavier workers at six month intervals. With this in mind, the use of heavy duty office chairs should be considered for all workers, as the grade and quality of such chairs is usually higher than average. The overall increase in cost for a heavy duty office chair is only around 30% with expected lifetime of these particular pieces of furniture almost double that of standard fare.