A few weeks ago, I cleaned them, and noticed they needed re-painting. On a subsequent weekend, I took all the loose paint off the windows in the living room, bathroom and both bedrooms. At some point, I've primed all of those. Yesterday, I did the top coat for the spare bedroom and bathroom. Today, I did the top coat for the living room (it took about nine hours). The main bedroom's still to be done, so that's another weekend.
I haven't even started on the study or kitchen windows, yet, so there's probably at least three weekends in that lot.