I recently had a 2010 CW Diesel in for an oil change at 67.5k. They found the cabin filter dirty and suggested the filters be replaced and the ducts be cleaned and "disinfected" for the "bargain price" of $160. I didn't accept their kind offer.
Ended up getting Ryco filters from Burson for about $40. I could have got them cheaper on Ebay but wanted to stick with a reputable brand.
A search on the forum provided good advice on the filter removal. The only additional info I'd add is re the clips on the side of the glove box. I found that the edge facing the seat need to be tilted into the glove box, that tilted edge grabbed with pliers and gently pulled toward the seat and into the glove box.
The filters were filthy, it's a wonder any air got through them. They were easily changed and all put back together in a few minutes.
From now on I'll probably routinely change these every 30k.