I was reading on APUG that a lot of modern papers have developer built in to the emulsion, so they don't keep as well as older paper, even when frozen. Whether this is to discourage people from stockpiling, or to make developing easier, or both, is open to argument. Some people believe this applies to Ilford materials. I think they claim a 3 year shelf life for MG.
I recently printed on some Ilford MG RC that I found at the back of my un-airconditioned closet. It had to be at least 6 years old, maybe 8. I didn't use it for anything important, but it seemed to work fine.