After reading the yeast book and threads I let mine go between 18 - 24 hours depending on the age of the yeast. If I am doing a step from an old vial I will let the first step go a little longer and the second in my 18 - 24 hour range.
Thanks folks. Let this one run for 24 hours then cold crashed, pitched into a Dreadnaught inspired DIPA( OG 1.097 and around 95 IBU) and it was fermenting away happily in about 3 hours. Running again with a 4.3L starter for the Rasputin's Folly RIS, bigger edition of my Anastasia's Revenge, which should come in with an OG around 1.13
i usually go for 8 to 24 hours. I pitch the whole starter and like to do it at high krausen if I can. It seems to me that i get a quick and figorous start to my fermentations that way. I admit i dont fully undersdtand the physics of yeast propogation but through trial and error this is what Ive found to work well for my purposes at this time
I run it for the whole time my starter is on....~24 hours then dump the whole damn thing in there. I have to admit though, I typically only do medium to higher gravity ales so I'm not worried about decanting.
It depends on the yeast strain and where it came from. If I am growing yeast from dregs, I'll let it run for several days. If I'm stepping up a liquid yeast from my inventory, 24-36 hours, though I usually am not in much of a rush to get it off as long as I have 24 hours to crash the yeast before brew day.
I also grow extra large starters to harvest from of all of the yeast I use. If I am starting from a dry yeast packet, it tends to take longer than liquid yeast to ferment out the starter, so I'll allocate at least 48 hours.