First store, 4 months. had 3 designs on maybe 20 different items. That store is still open, I almost never even look at it and those designs still sell... 8 yrs later.
Pacifier City - opened for 2 weeks before I got sales. I think it is the volume of pacifiers made and the fact that zazzle is one of the few places to get custom pacifiers.
My Random Ideas took about a month and a half. And this store is really just a mess of ideas. I really need to figure something out with it.
And I've opened and closed a few over the years...