Desires can be grouped in many ways. An easy way of grouping would be external vs internal.
An external desire is obtained from external sources and will cease to exist when the source goes away. Internal desires usually take decades to form thus are not expected to go away easily. Each desire has a trigger. When run into it, the desire will be activated.
Knowing where the desire comes from, helps us take control of our decisions.
Pursuing internal desires is better than external desires due to compounding effect. The external desire might fade away leaving us hating the thing that we're doing whether that thing is a job, a hobby or a business. On some occasions it might be beneficial for us to pursue the external desire. By understanding it we can put ourselves in situations where we are exposed to that thing more making sure the desire continues.