Ah, good differentiation. I do remember now, my account would state a date when my miles expired. Every time I had activity that date would be moved out 18 months. Never paid attention because I had constant activity in my account. It will be interesting to see how UA re-words their website to reflect that "rule change". They're so used to embroidering everything to reflect positively that I think it's quite difficult to tell what reality is.Members, please correct me if this is wrong. I have logged my understanding of this policy using the term "carryover":
Prior to the change, unused miles expired after a certain period regardless of account activity. Now, the miles will accumulate (carryover) as long as there is eligible activity every 18 months.