Originally Posted by
giorginho
From what I can see:
Gold > Gold: 18 months
Silver > Gold: no change - still 12 months
Silver > Silver: 18 months
Blue > Silver: no change - still 12 months
However there is a big difference between these "years": the Blue > Silver and Silver > Gold are based on a rolling year. Gold > Gold and Silver > Silver years are fixed from the date you moved up, if you retain the status year-on-year.
So a blue member doesn't need to earn *more* miles to move up. It's still exactly the same, but if there are no flights for 6 months then their tier miles in the prior 6 months are wasted.