It is unlikely that all patients will be revived at the same time. Those cryopreserved with more advanced preservation technology will probably be revived earlier than those with less advanced methods. Patients who were in a more damaged condition may not be revived until after patients with less damage. The date of attempted revival will depend not only on individual patient condition and the level of technology used when cryopreserved but also on the pace at which cryonics-related technologies improve.
Eventually, a time may come when revival technology will be perfected. In other words, it may be possible to routinely cryopreserve and revive people for medical time travel, space travel, and other purposes. As progress continues, it may then become possible to recover people preserved at earlier times, with less perfect methods and greater degrees of injury.
Some think it will take centuries before patients can be revived, while others think the accelerating pace of technological change might so rapidly transform our world that decades would suffice. Alcor has created robust mechanisms to care for the patients in its care for however long it may take. For more information see: Alcor Patient Care Trusts.