I always compare against the paid price on the same route. I generally won't redeem at anything less than 0.03 CPM at an absolute minimum. A good redemption for me is more like 0.06 CPM. Anything over 0.10 CPM is hard to find these days without PRs and really only comes into play on last minute bookings where the paid fares are getting really up there.

From back when the Asia rewards were the goldmine, I did YYZ-(AC J)-BOS-(LH F)-FRA-(LH J)-CDG-(TG F)-BKK-(TG F)-HKG-(LH F)-MUC-(LX J)-ZRH-(LX F)-YUL-(AC J)-YYZ for 120k miles. That was something like 0.30 CPM. It was a long time ago but I'm not sure that I should have been allowed to book that even back then. I haven't seen anything like that in a long time.