I just updated the wiki (for Flying Blue) as best I could figure out, after learning that Flying Blue has changed their expiration from 20 months to 24 months (2 years), and has added a couple more reset possibilities (current elite status that's high enough, not just lifetime status as before, and some -- but not sure which -- co-branded credit cards).
And that's it for things which reset all miles expiration, but just to make it complicated they added some things that reset the expiration of some miles but not others:
https://www.flyingblue.us/en/faq/cat...ll-about-miles (expand "
How long are my miles valid?"):
All your Miles are valid for life as long as you take an eligible flight on Air France, KLM, Joon, HOP!, Aircalin, Kenya Airways, TAROM or other SkyTeam partners at least once every 2 years, or if you're an Elite or Elite Plus member, or if you make a purchase with an eligible co-branded credit card at least once every 2 years. These "Overall extending activities" extend the validity of all Miles 2 years from the date of the activity.
You can also extend the validity of Miles earned with all other partners (airline partners not mentioned above, car rental partners, hotel partners, and experience partners) for 2 years by earning Miles with any of these other partners. These "Partial extending activities" with other partners will extend the validity of Miles earned with any of these other partners by 2 years from the date of the activity. Please note, "Partial extending activities" do not extend the validity of Miles earned from "Overall extending activities".
It's not clear to me, for example, which of the these two categories (if either) miles transferred from a credit card points program fall into.