I will add: some folks think the Wyeast smackpacks are kind of gimmicky. Not me. If I see no inflation within about 12 hours, I get a plan B lined up for my yeast, just in case. Being able to assess viability in advance of pitching is extraordinarily useful. But again, DOA yeast for me has been a very rare thing, only about a half-dozen pouches in 25 years of brewing (interestingly, IIRC they have only ever been Wyeast).