I'm on tray 8! Time is flying! I deliberately stayed in tray 7 a day longer than usual. Days 1 and 2 have been pretty sore for me and I was tired of spending my weekends being uncomfortable. I figure that Mondays are already bad, so... 

Anyway, since I got the attachments on, I've noticed that not every tray feels the same way. Four (especially top) was a real pain in the shark to remove. I thought it was just because the attachments were new... Then tray 5 was easy to get out which led me to believe I had mastered removal. Then tray 6 was even more challenging than 4, so I realized it wasn't just the learning curve of post-attachment life with Invisalign. Tray 7 was more of the same.  The first few days, I almost cried because the frustration of trying to get them out was overwhelming. And now, on tray 8, it feels like tray 5- relatively simple to remove. Even better, there was the usual day one and two "pressure" or uncomfortable feelings. I suspect different ones are having different effects/impacts on my mouth. I do see a different, especially on top. The bottom front teeth ares still pretty crowded but in pictures, I can see how the teeth behind them are getting in line.

When I moved to this tray, I was a little concerned that my teeth weren't tracking correctly.  There were a few that seemed to show a bit more plastic in tray 7. Then, these trays (#8) fit fabulously. I've also noticed that the trays feel lose on the last couple days of wear and the new one almost seems to fit better.