Storage rules for pre-recorded media?

I’m wondering if all of the same standards apply to pre-recorded media as to recordable? I’m so much not on about air tight storage and keeping them away from light. This I do - I am very fussy and that;'s kind of a no-brainer, but I’m wondering if it’s necessary to keep the media upright, or can the discs in their boxes rest flat on a surface rather than standing upright?

What do you guys think?