Unfortunately, many believers often treat the work of the Holy Spirit in their lives as if He is the water cooler standing in the corner of the room. Whenever they feel like it, they run over and push a button for a drink. God’s presence in our lives is more akin to the old-time water pump that must be primed to get started and used regularly or else it will rust up. Without daily use, the “pipe” leading upward to our thirst from the wellspring of the Holy Spirit deep in the underground of our heart will become empty and dry. Then, when we suddenly need His anointing, the water will not flow. For God’s “I wills” to actively and continually manifest in our experience, we must respond to Him daily. Speaking in tongues is one of the best and most useful ways for us to respond. Nothing clears and opens the spiritual “pipeline” better. As we commune in the Spirit we will come into a better knowledge of what God wills for our will, as well as a deeper understanding of how to exercise our will in the way He desires.
From the book "The Hidden Power Of Speaking In Tongues"