also beware out of date 'hard' grades
I have either bought up or been given the contents of a few darkrooms in the last 4 years.
I test old papers with a step wedge to see what the real speed and contrast range is of them. If they are fogged, then there is no need to tie up freezer space with those, and save them for lith development experimentation. Count the number of discernable steps once dry and you look up an Ilford data sheet to see what the grade is if you normally work with Ilford VC filters.
The graded non- developer incorporated papers usually are still free from fog for many years past thier expiry dates, but they end up printing as though they are about #2 or #3, even if when young they were rated as #5.
Another thing to watch out for is faded dichroic filters. I know that I can get a harder print out with a fixed ilford MG #5 filter than I can with the magenta fully dialled in on my dochroic enlarger.