<commentary> Form an engineering standpoint, there is no reason a 126
relay should outlive a 123 relay, unless internal components were all
replaced with ones with a much higher MTBF. The 123 relays are known
to
fail. Any relay will cycle so many times, then fail.
I will bet money (not much!) that most any such failure is not the
moving parts, but rather a bad colder joint that has developed due to
vibration or thermal cycling, or a dried-out electrolytic capacitor.
Not related to the number of cycles at all.
-- Jim
