Varies a huge amount. Some of those sites want weeks. Others will do it day of.
I just did my rounds today on a bunch of sites for my promos (25-28 and 26-2
and I've gotten confirmation of listings from five to ten outlets. I know there are some that won't get to me, but I am sure others will.
In general mu suggestion would be to make absolutely sure that you have a good, solid face (cover, which was weak last promo I did, was not helping me as well as blurb and sample) to lead with, have as many reviews as you can, and apply a week in advance if possible. Longer is probably better.