Originally Posted by NickB

It used to be the case that the only way to extend miles was through an activity that generated what as then known as 'status' miles (now XPs), i.e. essentially flying on a revenue ticket (or spending on some affiliated credit cards).

That system is still in force for miles acquired through flying or miles acquired by any means if there has since been some miles-earning flight activity. Most people here are AF/KL frequent flyers and therefore their experience will match that situation. I suspect that is why they only consider revenue flying or affiliated credit cards spending (or XP crediting) as valid moves to stop expiration.

What has changed in the last few years (can't quite remember when the rules changed) is that, for miles credited to the account exclusively through non-flight activity and where there has not been any flight earning activity since the miles were earned, the miles can be extended through non-earning activity. So, for a minority of FB members who do not earn any miles from flying, there are indeed alternative avenues to stop expiration. Clearly, FB miles earned through hotel or car rental partnerships, FB shopping portal, etc... would clearly qualify. I do not personally know whether credit card transfers themselves do qualify for that purpose too but the threads I referenced above suggest that such transfers do indeed qualify. As I do not have any direct experience myself, I would not want to take a position on this, hence my suggestion to peruse existing threads on the topic.

Originally Posted by Fabo.sk

I'm not sure what you are hitting on here. None of the posters are in conflict.

What has been said:

1. That only a flying activity extends all miles. That is true, though in your specific case you only had miles from credit card transfers, so a card transfer was enough to extend all your miles.

2. That miles prolonged until December 22 expire in December 22 and that's not the date when a 2 year countdown starts. Your miles, by your admission, were set to expire October 23, so they were not at all impacted by the pushed expiration date.
You did confuse the situation by wording your post as if the expiration date was December 22 or earlier. If that was the case, your miles would not have been safe. Your 1000 mile transfer would not prolong them because it would have arrived after the rest expired.

Originally Posted by NickB

As an aside, if you never normally credit flights to FB, the problem with taking one DL flight (or flight on any other ST airline for that matter) to keep the miles alive as some suggested in this thread is that, from then onwards, you will only be able to further prevent expiration of these miles through crediting another flight. For some, it might be better to have some other non-flying activity so as to retain the flexibility of being able to further extend the validity of the miles through other means.