I travel almost every week and go through the usually cancelled/delayed flights for which I am often giving Electronic Travel Certificates. At any given time, I have several but they usually end up expiring. Where in your account or app can you see these? That's one of the reasons mine always expire as I am unaware of how many I have.

Also, can anyone point me to clear summary of the rules? I'm sure it has been done on this site before. They seem to be pretty restrictive. I tried to fly my son home from school for the Holiday and they wouldn't let me use it.