Originally Posted by uechikid
It was my understanding that if you are going to reuse yeast, that you should get it from the secondary. I was also under the impression that yeast can last a long time if refrigerated.
You certainly can keep it a long time! I have used yeast that was in my fridge for a year or so, with good results.
I wouldn't reuse yeast from the secondary, though. That is the least flocculant, most stressed yeast of all. It's been sitting in an alcohol rich environment longer, too.
Yeast from the primary is fine to use. The yeast in the secondary will be "cleaner", but a quick yeast washing takes care of any trub from the yeast in primary.