The double PQM one for 2010 started around April; in 2009 it started around March. There's usually a Mastercard double bonus miles (not PQM) before that. But it's very tough to predict. If US is going to court anyone currently flying UA/CO looking for a change based on what they don't like about the combined UA/CO program, US may roll a DPQM promo sooner than that. It's all speculation though; there might not even be a Q1 promo. Take your chances: book sooner for better fares, or hold out longer for a chance at a promo. I'm in the same boat, and also eagerly awaiting a sale on a couple of trips I need to book.