Record Collecting

Something that’s puzzled me… why do some record covers get ring wear, and others not? I realize that one factor would be whether or not the record is in a sleeve, but are there other reasons?

The ring wear is an indication that they are being packed too closely together on the shelf. Plastic jacket covers are available to help prevent this. Also, I’m sure that cheaply made jackets are partially to blame. I have over 400 albums and some have ring wear and some do not.