These nail clippers are great for very large dogs, or nails that are curling around or ingrown. I used them for many years at an animal hospital I worked at, and we had the same pair for all that time....they are durable! Also, unlike many other nail clippers the spring in the middle never became loose or fell off. Naturally, they would become dull, but you can always send them in for sharpening. If they did become dull, however, they would crush the nail...even the large ones. Also, if not sharpened, in addition to crushing the nail, it snapped your finger between the handles or frayed the nail. These are too heavy to use on smaller nails like puppies, cats, or bunnies. The handles were pretty comfortable. Additionally, I never noticed any rust on these clippers. Many other nail clippers always rust in the middle where the screw is. Finally, I wanted to mention that if the clippers were dull, the dogs seemed to HATE the nail trim.