There is a fair amount of debate about this. Blocks with sharpeners do allow you to hone a blade every time you use it, which keeps a knife in workable condition. And it will certainly save you time, especially if you don't enjoy sharpening your knives. However, most built-in sharpeners don't have the best reputations, and they can't restore a blade to like-new sharpness. If you're okay with "sharp enough" knives, you'll probably appreciate a block with a built-in sharpener. But if you want your knives tip-top shape, then you'll need a more hands-on way to keep them sharp.