How long til Google pagerank is updated?

I know we just went through an update, but that was the first time I was paying attention. I never cared about PR before! How often does Google go through a pagerank update?

--Colleen

 

Recently I see Google updates quite often, correct me if I am wrong, roughly weekly or biweekly?

 

http://www.seocompany.ca/pagerank/page-rank-update-list.html read this i think it will make u more clear

 

Usually they update it per 3~4 months.