Don't forget that handlebar height also impacts saddle and lower back pressure.
In my case I tend to remove a spacer from the stack later each season, and put it back early the next season. As I accumulate the miles I become more acclimated to holding the posture for hours, and I feel more comfortable with a slightly lower placement. Earlier in the season I'm not quite as bike-fit, and I prefer a little more relaxed geometry. This also coincides with number of miles ridden; if my early season rides are shorter, I don't mind a little more saddle pressure from a more relaxed handlebar position. Later as my rides increase in length I prefer less saddle pressure.