I had trouble the first night I had my trays. I actually cut my lips up, but that is just because I didn't know what I was doing. Once I figured out how to get them in and out, they are simple. I lost 7 lbs the first week of my treatment, mainly because I was afraid to drink anything but water with them, and I skipped breakfast everyday. I am just about back to my normal eating habits now, since I have adapted and learned how to eat something really quick, brush my teeth, and get them back in. They are working great for me.