And also keep in mind that even though declawing is really inhumane for an animal, the owner may have already made up her mind about having it done. If that is the case, suggest to her that instead of using clumping kitty litter, or kitty litter at all, she should either use shredded newspaper, or (don't laugh) rabbit food. Because the litter gets into the areas where the cat's knuckles have been removed and it gets really painful. Suggest to her that getting a natural wood scratching post will blunt nails, that cats can be trained NOT to scratch and you can provide her with how to do this. I have 9 cats and fine furniture, and the only piece of furniture my cats will claw is an old sleeper couch in the cat room. Cats are very intelligent and if you can communicate with them in ways they understand they can be trained. Good luck. I just lost this fight with my stepson. No matter what I said his wife was adamant, their calico was going to be declawed.
So know going in, that the mind may already be made up, and good luck this is a volatile issue no matter what!