I never had declawed cats. It takes a few weeks of training and cats know where they can scratch. When you have to leave your cats alone, for work or else, you can put old blankets on your furniture and spray some repellent on it. It always worked for me. Spraying water is efficient also. Cutting nails help too. It is true that some declawed cats have the tendency to bite when they play, and it can be unpleasant for humans or other pets. Also, for some cats, their paws can be painful for their entire life; I knew one that would not go in its litter because he could not scratch and bury his "production" because it was too painful even after a few years. In short, I am totally against declawing.