I've always made it a point not to listen to score before I went to the theater. I wanted to have the experience..... "as presented". When I first started going to the opera I kept to that policy....however, I frequently found myself struggling to keep up with what was going on. My first viewing of Parsifal was unfortunate as I could barely figure out what was going on...much less the opportunity to enjoy the actual production. Since those early opera viewing years, I now make it a point to listen to a recording before going....when it is possible. By that, even when I do not understand the actual language being sung I have enough of a background to appreciate the particulars of the performance. For me, I find it rare that knowledge of the plot to an opera becomes a spoiler.