I'm having the same problem right now. Bobandy and Scully are destroying the new dinning room chairs. They have plenty of scratching posts but they'll still go to the chairs. After trying deterring sprays, moving around the scratching posts to more convenient locations, etc I had to get nail caps or soft paws.
Just make sure you don't buy them big (they come in small, medium and large)
Bobandit is a medium sized male cat and small are good for him. If you apply them too big it might cause infections or wounds. Aside that they're really good and declawing is absolutely out of the question. Not an option for us.