Distinct objects, proportional texture size

I haven’t found any topics that could have helped me so I decided to post a new one. My purpose shall be quiet a common thing I guess so I’m probably missing some basic point of UV mapping and texturing with cycles using nodes.

My problem is the following: I have two separate objects, a smaller and a bigger one -with applied scale and rotation properties (so there’s 1.0 everywhere:) - and a brushed metal texture which is assigned to both of them, and I just can’t get the textures to appear in the same size on the objects in the rendered image. Which means the brushed metal on the smaller object has shorter scratches -so a higher “scratch-density”:)- as the same texture has on the other object. Maybe I could play around with the size of the image file I use or with the scale properties of the mapping node between the texture coordinate and image texture nodes for each texture, but the result still wouldn’t be perfect and I’m sure there must be a better solution. I bet I should do something with the UV maps of the objects or I don’t know. Why doesn’t Blender render the textures in the same size regardless of the dimensions of the objects? Here’s an example: if I have a house made from laths of different size, they textures will look different although they are made from the same kind of wood.