The question of whether some crystallization will take place in old glass during long-time storage (up to 1000 years) at low temperatures well below T_g is considered theoretical. Evalua-tions for the systems, Na₂O.SiO₂ and Li₂O.2SiO₂, are carried out using the model of homo-geneous and heterogeneous nucleation theory. For these systems a barely observable crystal-lized volume fraction will be reached at 300 K only after storage for astronomical periods (10₆-10₁₃ years), depending on the number of heterogeneities and the contact angle of heterogeneity.If the observed strong influence of H₂O content in glass on crystallization is also taken into ac-count, crystallization will not take place for at least 1000 years of storage at 300 K. This limiting value is close to archaeological periods and will therefore merit careful attention in further investigations. -- AATA