Many service companies will be billing clients once the work is complete, which means that a timesheet system is not needed. Merchandise companies are in the business of selling products, and will usually only bill an account when an order is placed. So if you ever find yourself at the office diligently working away on your computer when you should be getting some rest, then I bet you know what’s up. That’s because merchandising accounts need to know what time they have been using for billing purposes, and so it makes sense for them to keep track of their hours on a timesheet.