I've always gone by the mentality of leaving things rest a few weeks at least. When you do then start linkbuilding set some tight criteria, such as extremely relevant high pr and low obl blog comments, high quality and unique article creation, etc. Over time as your site builds up a little authority then you can loosen the reigns a little at a time. But keep things consistent.
I'm sure everyone's different, and I've found it's mainly down to trial and error.