How many years of helium is left?

As a keen observer of the latest developments in the field of energy and natural resources, I must inquire about the current state of helium reserves. Given the increasing demand for helium in various industries, ranging from cryogenics and spaceflight to magnetic resonance imaging and nuclear fusion research, how long do experts estimate we have left in terms of years? Are there any new discoveries or technological advancements that could potentially extend the lifespan of our helium resources? Furthermore, what strategies are being implemented to ensure a sustainable supply of helium in the long run?