The primary flaw of much advice given around the topic of “how often should a blogger blog?” is that it involves examining popular bloggers and deducing what they must have done to become popular. This approach presupposes that your goal is to become a popular blogger, and that you have the resources to accomplish this goal. I’m not going to offer this type of advice because it doesn’t apply to most bloggers who have “day jobs” which preclude this degree of focus on blogging.
Instead I encourage you to consider your audience and consider your own motivation.
Your audience: no one is making potential readers read every word. Whether they discover new posts by tweet, LinkedIn update, Facebook post, email notification, RSS, or browsing the blog, they can simply decline to read posts that don’t interest them. There is definitely a saturation point, but two posts a week isn’t too many–if that’s what you want to do.
On the other hand, it’s probably not ideal to have very long gaps between posts. New posts are more likely to be read by readers who remember enjoying preceding posts. Which suggests a strategy of spacing out posts so as to cover gaps. For example, if you anticipate being too busy to blog, or perhaps going away on vacation, you might want to hold back your posting frequency to allow you to cover the gap. Many bloggers are shooting for weekly or every-two-week posting.
Which brings us to your motivation. One can blog entirely for one’s own gratification, of course. Ironically, the more you enjoy blogging, the more interesting it’s likely to be and the more you are likely to blog—which benefits your readers also. So please take seriously the question “how do I make this fun and meaningful for myself?” Is it going to be too much of a chore if you set too ambitious a pace? Are you going to feel demotivated if you set a rapid pace early on, then can’t keep up? Or perhaps by blogging as much as you can early on you will get into the hang of it—writing isn’t like riding a bicycle, it’s more like a competitive sport or musical performance, we benefit from recent practice.
So I’d say focus on your motivation, try what feels right, and be prepared to experiment / adapt over time.