I applied to the exact number that I intended to apply to all along, ten. I must say that the last few applications probably didn't receive the treatment that earlier apps received. For my Stanford app, since it's such a long shot anyways, I decided to go with free-form thought and writing. I thought out exactly what I wanted to say, put it to paper one time, and did not revise again, editing only spelling and grammar. We'll see how that turns out.
The Haas deadline (R3) was about 3-4 weeks after all the others, and after taking a break I found it tough to get motivated again. Haas is a personal favorite, and my recs, scores and transcripts were already in so I went ahead and did the application. If it were any other school, I probably would have dropped it at that point. I'm a little disappointed that the application was probably not my best work; but it's had to predict how Adcoms will view any set of essays anyways.
I did change my mind a lot about which schools to apply to, and which were my favorites. With about 1 1/2-2 months before R2 decisions are announced, I could imagine that preferences could still change some more.