The strips are easy to peel off and apply to your teeth. I have only use the 30 minute strips so far and I tend to keep them in for longer, between 45mins - 1 hour at night before going to bed. I have noticed an uplift in colour shade and only once did I have gum (slight) pain whilst they were on. I think I had the strips I bit too high on to the gum line. My teeth are not particularly too discoloured although I do think a second pack will be needed to get a more noticeable whiter appearance. These were recommended to me by a friend which is why I purchased them and she has bright white teeth and has used several packs.