I think consistency is important. If you can put up something with quality every day then great! I can't (yet) so I've settled on one new post every third day. Find what works for you!
If you want traffic rather than just links to your blog, you need to post atleast everyother day. Anything else leaves hungry readers dissatisfied
i am for at least 2 posts per week.It takes a lot of work coming up with a new fresh article that is relevant to your audience.I wouldn't be able to manage 7 posts a week.Time does not permit.
If you want to rank for some given keywords, then you should upload often. But once you are satisfied with your rankings, you should greatly reduce your upload frequency or you may fall on some of the keywords you are already ranking well for.
That's like asking "How much time should I invest in improving my business"? If you think of it that way, you will want to post as much as possible. People read blogs because they are updated with new information regularly, the longer you leave your readers looking at old content, the greater the possibility that they will just move on to a blog in your niche that is given more attention buy the author.
As many as you can but it is fine if you can make only one post per week The most important is maintain the quality of the post