Different woods have different degrees of hardness and density which will affect how they look over time. Eastern White Pine, the softest wood used for flooring, has in many cases withstood over 200 years of use and abuse. You’ll never “walk through” a wood floor.
Hardness and response to moisture are individual to each species, and these properties are important considerations when choosing a wood floor.
The hardness of wood is measured scientifically by the “Janka” test. This test measures the pressure it takes to sink a .444 inch steel ball one half its diameter into the surface of the wood. A higher number denotes a harder wood. Woods that are naturally harder than others will show less dents and evidence of traffic, but this relative standard is mostly for cosmetic reasons as all wood floors will last hundreds of years before they are worn through.