Grass deterioration was introduced in City Folk, and remains in New Leaf. I didn't pay much attention to it in City folk, and I've heard there have been changes to grass deterioration in New Leaf.
What causes grass to deteriorate, how can I prevent it, and how do I fix grass that has already deteriorated?
I'm not sure if it remains in New Leaf, but to prevent it just don't run. That's what I do. You get used to it. You can run on bridges and the beach (and I believe in the main street grass) but not in the town itself... if the same spot gets run over too much the grass will deteriorate.
Animal Villagers and Player Villagers may use wear of the town. The process is minimal and may be reversed by planting flowers over the area; using a template may wear it more out if used for running often. Snow does not make the town filled less with grass as fast as CF.
Birds are more often the ones that have traces more visible. Players can notice footprints scattering to grass after running in ground patches. The wear and tear feature is minimal.
