Every religious and spiritual endeavour results in people asking the aspirant to renounce desires. Even if you try to run a little experiment on yourself for a day you will quickly realise the futility of this task. It is almost impossible to force yourself to control or eliminate desires. However Vedanta says it is not desire per se that causes the issue, but the set of conflicting desires. It begs a human to fix on that single inner calling and work relentlessly in its pursuit.
Desire creates two things in every one of us. One, energy. Two, effort. It is because of aspirations that we take efforts towards gaining something. It is also the sense of gaining it and the possible resultant happiness that creates energy and helps us sustain the along the path. Both of these drive action. Without desires it is very difficult of us even to visualize acting or working. If we make an effort to understand what this spiritual path and what spiritual evolution means we can utilise the above two forces generated by desires to help us steadily advance on our spiritual quest. The intention behind action while not visible to the whole world can help the individual make progress.