I'm good about regularly trimming their nails but I do use the same type as Redhedd, it is easier to use. Ripley will lay in my arms while I trim his, Scout I have to do while she's sleepy and Richard holds Jazz while I do it.

One other thing to keep in mind is the type of scratching post. Maybe you should also get a carpeted one in case someone prefers that. My cats will not touch anything sisal. The breakdown here is such:

Ripley loves extra tall carpeted posts only
Jazz loves the Alpine cardboard scratcher - she only uses the post to stretch on.
Scout will use either but claims the posts and chases Ripley away from them so I have to have plenty.

I really think you ought to get an alpine scratcher as an alternative for them. Just be prepared to clean up cardboard bits frequently.