For me, it's always within 12 hours. But I've read of many other writer's that haven't been so lucky with it taking a few days, even longer (I'll keep my fingers crossed for the future).
With the series you've got going, put some serious thought into doing preorders (for 2nd/3rd book)--like Tim is saying^^. Preorders aren't too useful for 1st books, but for series books ready to go, you might get a lot of momentum.
People who are against preorders are often not considering the extra publicity through hot new releases, fans, and readers who are waiting to binge. But I do think that if you have a single book only, holding off on preorders might be wise (unless you already have a big fan base).
edit{ for clarity