Well, I donate every month but I won't donate until I see what the item is. Normally that means I don't donate until the very end of the month. The reason I don't is that there were at least two months when I donated early and never got an envelope at all, and I had to email tech support before I did. That's happened to me at least twice, so now I never donate until it is released because I don't want to take that risk again.
So I would rather the item be released as early as possible because I won't donate until it is.