Vision is akin to a roadmap. Just like a driver uses a roadmap - electronic or paper - to chart a course, likewise your God-given vision is meant to be your navigational aid in life.
Without a vision for your life, you will lack direction and ultimately live a life that falls short of God's best for you. Pro 29:18 KJV says that the people perish without vision. The NKJV says that the people cast off restraints. Pro 29:18 is simply saying that when there is no vision people will live aimless wasted lives. An aimless or wasted life might as well not exist, hence the scripture says that the people perish. An aimless or wasted life is a life that is or was lived contrary to God's plan and purpose.
God who created you is the source of your purpose. There is no manufacturer who creates a product without a purpose for it. So if you want to know the purpose of a thing then go to the manufacturer. If you want to know how to best utilize the product then go to the manufacturer's manual for the product.
God is ready to reveal His purpose for your life. You must spend time in His presence to discover your purpose. Then spend time in the Bible, the manual for your life. As you devote your time to both of these, God will inspire visions for your life that will enable you to reach major milestones on the way to fulfilling your purpose.