I recieved these in the mail, and used them the next day. I hadn't whitened in about 4 years because I wanted to avoid doing so while pregnant or breastfeeding.
I found these failry simple to use, and they did stick well.
The only thing that was a bit frustrating, was that there was still stuff esacping from the strips and getting into my saliva, so I had to keep going to the bathroom to spit out my saliva.
I did find that my teeth were whiter after literally the first use!!!
Overall, I'd use them agian.