How often do you like to post to your blog? How often do you like to see posts from blogs you subscribe to?
This only matters if you want to increase the traffic to your blog, but I've read that once to twice per week, even doing 30 day blogathons where you post once a day for 30 days is a great way to increase subscribers and get new traffic. I just started a new blog so I'm posting daily for awhile until the posts climb in number.