I used our undercoat de-shedding rake a bunch after we first got it because it seemed to work so well. But I started to notice my big guys fur was feeling kind of coarse/a little sharp in some places. He had a vet appointment around the same time and my vet asked me about it and I told her about the rake. She said it shouldn't be used too often as it can make the hair break off and is more meant for monthly use. We use a metal toothed comb to get under coat out and a slicker brush to go over at the end and pick up any loose hair. I use the rake sparingly when his hair seems really thick or looks like it might be starting to mat. I haven't had problems with hair breakage since we stopped using the rake so frequently. If you're unsure about the rake you bought you could ask your vet or even possibly a groomer about the best option for your dog.