Charlotte had been married for several weeks now, and one thing she had learned in that time was that the appearance of being just in time was to her benefit. She had never been one to be late for things, so that was not the problem. Rather, she had quickly learned to time her preparations so that she would not be ready too soon. There was no advantage to being ready too soon. On this particular day, they once again were expected to dine at Rosings.
One of the first times she had dined there after moving into her marital home, she had found herself ready to go a full hour before their invitation, and as it was not a long walk, her husband ended up finding various tasks that he asked her to do with an extreme sense of urgency during the time before they set out on their walk to Rosings.
The next night when they had an invitation, she had not intended any delay, but she was ready just in time to leave, and despite the sound of panic in her husband's voice, he was not angry, and they were equally prepared for the dinner itself.
The following night they were once again asked to dine, and in the morning, Charlotte thought of how to arrange her time so that she was once again ready exactly when they needed to leave, and no sooner. She was ready a minute or two earlier, but not enough to be given additional tasks which were unnecessary before their departure. It was perfect. His sense of importance required a certain sense of urgency, and she would provide that.