Originally Posted by
aopluu
I can transfer out prestige card point to airline before closing it
Just be aware that most of TYP's airline partners have horrid "hard" expiration policies, meaning it's impossible to reset them no matter what activity. The only ones I can think of offhand that are fine to "park" at are Avianca (one year expiration but resettable through for example another transfer) which is in Star Alliance, Virgin Atlantic, and JetBlue. Flying Blue expiration can only be reset by a paid Delta (or other SkyTeam) flight, credited to Flying Blue, every 20 months or less.
Originally Posted by
aopluu
3. per your pro-explanation, no matter I close/ downgrade/ product change, the clock to set for Thankyou family card is from "Today" to count 24 months, not from "1 year ago" when I got the prestige
Not necessarily, but it's not predictable: If the new card you convert to has the same account number after conversion and is in the same program, it apparently doesn't reset the clock. But you cannot know whether you'll keep the same account number ahead of time; you can just downgrade to TYP Preferred and hope that you do. (And that will keep your points alive, and allow you to transfer them any time to Premier for transferring outward.)
So I would say Preferred might be safer than DoubleCash, and certainly worse than it.
Plus sometimes Citi targets you for 5x earning promos on Preferred:
promo 5x TYP on restaurants, gas, grocery, drug, mass transit
which (if you got such an offer and acted on it) would add to the TYP points you could transfer to Premier. That wouldn't be the case with DoubleCash.