Most manufacturers’ datasheets specify 20 or less years of data retention (even when powered on). This might seem like random sufficiently large number, but the

Most manufacturers’ datasheets specify 20 or less years of data retention (even when powered on). This might seem like random sufficiently large number, but there really are devices made in mid-90’s (notably early FastEthernet cards) that do not work because they lost contents of their configuration EEPROMs.