I do not remove the selvage when I purchase fabric. I will save a sample of fabric with one complete printing of the info that I can take with me if needing to match the fabric or pick out another fabric for a project. I also like to keep a fabric journal where I record information about new fabric in my stash. I list the name of fabric, how much I purchased, what the fabric is made of, the price and where I bought it. I also list the pattern or project it was purchased for and source.
I find it fun to follow the fabric from purchase to completion of the project. Many times this info helps me decide if I want to use the fabric for things I want to sell and what to charge.