80 / 20 is just a concept of prioritizing. Does prioritizing work? Yes... so it works. Whether it is 20% or 14% or 21% doesn't really matter.
For another example, at a store where i used to work, i once asked the manager/owner who our best customers were. She did not know! (She should have). So i was asked to find out. And what i discovered going through records was that our top five customers... out of HUNDREDS every month... generated almost 20% of our entire income! From there we could study what kinds of customers generated the most business for us, seek new customers of that type, as well as be certain we treat our best customers well and seek to provide additional services that they needed so that they would choose to remain with us rather than go to competitors. For us, corporate accounts for companies that offered first rate products and services generated the most income for us. They weren't necessarily the largest companies (certainly not employee-wise), but they offered quality products and services on the regional, national, or international level that were rare: A company that built and repaired medical lasers, a company that repaired racing and other rare engines, a company that published thick glossy catalogs as their specialty, a company that designed microchips that were to be inserted in water faucets overseas and then imported to the U.S., and a lumber yard that supplied to construction companies that in turn built housing developments.
If you know WHICH customers generate the most income for your business and what their needs are... this might be the "20%," depending on how much variance there is in purchasing with your company. Winning just one more of this type of customer would be more valuable than winning perhaps a hundred, or even a thousand, of customers who use less of your products or services or who are less likely to use you often. It is less work to serve these accounts than customers who do not regularly buy from you.
