Is it better to post on your blog every day or once every couple days?

I have heard that it is a good practice to post on your blog every day for SEO reasons and to keep articles fresh.  But, I have also heard that it is better to post every couple days, because it is better to research a topic and give quality posts and give time for comments.  Which do you do on your blog and why?  I am new to blogging and would love to hear everyones thoughts on the idea!