Google Refresh Cycles
ll webmasters show interest in the ranking of their sites. It is clear to very few, however, how the ‘Google clock’ functions. Answers to that are usually derived from experience.
According to Google’s information for webmasters, one might have to wait a month for a site to be indexed properly. PageRank (which directly affects traffic and search results) is updated/re-shuffled every 3-4 months according to a rumour at the SEO newsgroups. The rumour also says that the next PR update is in the beginning of April 2005.
A re-direct is said to be the safe solution to preservation of PageRank when moving between domains. Nonetheless, this may not work perfectly, not immediately anyway.
Google Suggest appears to have a long update cycle; Google Images likewise. I estimate it to be about 3-6 months.