Originally Posted by brewhead
what would be the advantage of reusing the yeast? most kits come with a new packet of yeast. would i be improving - or speeding up the process by reusing the yeast?
What I reuse is liquid yeast. I rarely use dry yeast. I would not reuse dry yeast. As you said, it's free with a kit (but I don't do kits), but it is cheap enough.
Reusing liquid yeast from a primary definitely speeds up the activity when used right away. It is comparable to making a yeast starter, but with fewer steps.