It depends a lot on the look and feel of the surface itself how you should recreate it, some require a lot more work than others do. I've created a few rough materials in the past and i can think of a handful of them requiring extraordinary texturing and materials with numerous layers for exact control of reflectivity, roughness in multiple layers, numerous bumpmaps and so on..
Ofcourse the better and more detailed your models are the better your materials will look once applied to them and complex materials requires nice clean UV's to avoid stretching and scaling issues so keep that in mind.
The problem with repetition over larger surfaces could be a issue but i try to get around that problem by adding larger and smaller procedural noises, or any type of textures to break up the repetition where it stands out the most. You can cover some of it in dirt if that fits your type of mesh. Some parts can you hide in shadows and with foreground objects such as bushes and trees if it's a building you're working on.
Depending on the mesh and it's uses i sometimes handpaint all maps required, everything from bumpmaps to specular, SSS, reflectivitymaps (roughness), gloss and more. Most of the time you can get away by simply throwing on a couple of highres textures, seamless or non-seamless both work fine to give the surface some irregularities.
What really matters (
i think) is the details, the stuff you can barely see.. some may say it's pointless in wasting time on such tiny details but i disagree. Everyone can make a materials with some textures in it, but not everyone can go beyond the standard and if you can do that then you can do anything. And your renders will stand out from the rest which is a nice bonus!
/ Magnus