If you don't really listen, you will miss out on what your prospect actually needs.
Research shows that 43/57 seems to be the golden ratio: 43% of talking done by the salesperson, and the majority with 57% done by the prospect.
But not only the quantity, also the quality of listening matters. Don't interrupt, listen to emotions and don't assume anything. Clarify, ask more questions and summarise what you have learned. These little steps will help you to listen … and to hear your prospect!