"How often should I blog?" is definitely a 'frequently asked question' amongst business bloggers.
Embarassingly, it's been TWO WHOLE WEEKS since I last blogged! That is so naughty and not at all what I advise, but it does serve to demonstrate how challenging regular blogging can be if you are busy working 'on' as well as 'in' your business. Not that anything 'bad' is going to happen - it's just not good.
In my view, people who are blogging for business should blog at least twice a week. The only situation when blogging less frequently might be okay, is if your business blog's readers' expectations are set that way, or if their lifestyles are so busy they probably won't mind less frequent posting. But neither of those factors have anything to do with search engine rankings, so if you want to please your audience and the search engines - twice a week's the way to go.