Hmmm - just gave up on some 1999 yeast, as it finally quit risin to our specs.
Freeze it, lasts a long time.
I have pretty good luck with mine. Keep it in the original bag in a Tupperware cannister. Only take it out of refrig. long enough to spoon out what I need and then immediately back in refrig. That reduces sweating inside the container.
Using Fleishman’s right now, but really prefer Red Star yeast.