I have found RC paper to not last. VC fiber paper will lose contrast which isn't a big deal depending on how you print. Benzo can save papers as mentioned above. I read a long time ago that the papers that predated the removal of Cadmium last longer. That seems to be the case sometimes. Older graded papers seem to fare the best for longevity. I have used papers from as far back as the 40's that worked.