Truckers need to know their Cost Per Mile (CPM). It's a critical number to know whether or not a load or an average of loads is profitable. Calculated into that figure are fixed expenses, the monthly expenses that must be paid no matter what, and the operating expenses of day-to-day operations. Obviously, whenever you can cut the costs of your monthly expenses and operating expenses, you're going to do that, because it makes you more profitable, it makes you more money, and making money is why you're out here in the first place.
Oddly enough, retail, restaurant and other types of businesses have the same kind of deal. It's called the Cost of Doing Business (CODB). Basically, they add up all of their purchases and expenses, including salaries, needed to run the business, then they divide that by the number of days they are open, giving them the minimum amount they need to make each day in order to break even. If they are consistently in the red they will either go out of business or they need to make changes to their CODB. They can raise the prices of goods and services, but that doesn't always work in a free market, because if consumers can get the same thing cheaper elsewhere, they will. The alternative is to reduce the costs of purchases and expenses, including salaries, in order to reduce their costs of running their business. Doing so keeps them in the black, makes them more profitable, makes them more money, and making money is why the business exists in the first place.
I will leave it to the reader to discover any similarities, differences, hypocrisies and ironies that can be found in comparing the above two paragraphs and situations.