I have been using one per flight, every flight. The bad news is the Bonus Miles offers have ended in March High Life (and the Lily O'Brien's collection has changed to a different 6 quid box - maybe FTers bought the entire year's stock already!). So I've been using them to just buy the 10 quid Lindt box anyway for 20 free miles. Take that Marriott, how'd ya like dem earnin' apples?