Oh, I don't mean to say you shouldn't write often! But I also think it shouldn't be a source of pressure and stress to blog daily. And if you find that your quality posts are getting "watered down" with posts about what you had for breakfast because you felt like you HAD to blog, it may end up costing you readers.
I think it is more important to ask yourself with EVERY post-Is this interesting, relevant and engaging? Or is this filler?
If you can write a killer post every day, that's awesome. But if it's not happening, don't force it! Be critical of your own writing, and if what you wrote today feels like a rambling brain fart that's not going anywhere (I have so many of these! Like this comment!), don't publish it! Even if you spent an hour on it! Consider it a writing exercise. Maybe it will turn into something great later that you can be proud of, but hold off until then.
A few years ago, before RSS feeds were the norm, there was great pressure to blog daily-people would go to each website and if there was nothing new EVERY day, you got chucked from their reading lists. But now with RSS feeds and readers, you won't be frustrating anyone by not constantly updating. The goal is to get into someone's Feed Reader. Once someone subscribes to your RSS Feed, you're golden. And the best way to do that is by having great content.