Hi! Even though it is important to update a blog at least 3 times a week (especially if you get money through adsense using it), I have to confess that I update 2-3 times a month, tops. Life gets too busy... It is important to update as much as possible, adding the right tags, doing good SEO, adding pictures and tags on them. If you can, do it 2-3 times a week so your chances to rank as more relevant are higher. Google values that a lot.