It depends on the story. If I'm absolutely and utterly in love with it, as in, can't think about anything else, I'd want and update every hour lol. If I loved the fic but wasn't obsessed I guess once a week is alright. Honestly it just depends on how much I like the story, because if it's not that good, really fast updates are annoying.

i think the number of updates per week doesn't really matter.
so long as the storyline's good, regardless of its characters,
i'd get into it.
that's just me though.