I heard from an old neighbour that back in the day, she used to put up new wallpaper every spring. She said that in many cases, people wouldn't strip the old wallpaper, they would just continue to layer it on year after year.
We took down some wallpaper in my parents' place recently and underneath was a mermaid motif. Years before I could remember, that room would have had a totally different character. The light would have been absorbed in a much different way. I think I have completely underestimated wallpaper and its leverage.
Maybe I should not so blithely skip that step in my spring cleaning.