Glassy materials have been plagued by their thermal stability since their inception. To ensure safety in their use, people have always endeavoured to improve their durability and stability. Can glass maintain long-term stability over the years? What are the physical mechanism and basic factors that determine its stability? These are important problems that have long been of concern in the field of glassy physics. Based on our research on the stability of amorphous alloys, the present paper will briefly describe the origin of glassy metastability, how stability can be maintained for a long time, and how to improve the thermodynamic and kinetic stability to produce ultrastable glass. Finally, the material factors affecting stability are identified to address the efficient manufacture of high stability glass. A full understanding of glassy stability can not only ensure safety during service, but also is critical for understanding fundamental physical problems such as supercooled liquid and glass transitions.