In addition to packing a separate package for a single day, I've found that using spacebags to store certain items gives a little bit more room so other clothes don't have to be packed as tightly. The secret is to not take more with you now that more room is available. I usually have more of a problem with creases. Maybe I should try rolling!
Mark - I used to allocate about the same time, but as of April, I'm allocating more. Because the one time you think you have everything and then, getting out of that first shower, realize you forgot to bring clean underwear, you'll remember it.