Join Date: Oct 2007
Location: LONDON
Programs: CX DM, BA G4L, QR PLT, EK PLT, Hyatt CC, HH DM, SQ SLTRE, BonvoyTit, UK SL, VS Wings, UA, DL, AA
Posts: 1,756
Look at your last ten transactions - the last date on which you earned or burned would be the start of the clock and its 36 months from then.
In AA's case its 18 months but they are far more clear about it on their website, wish BA would do the same