Following my change of domain name, I have done a 301 redirect of my old domain to my new domain, to reap SEO benefits therefrom and recover as much of my backlinks as possible. I know it may take sometime for the old domain backlinks to be transfered/recorded for the new domain but will there come a time when the full transfer would have taken place and all SEO benefits fully accrued such that I can then dispense with maintaining the old domain? If yes, how soon is this?
Just a suggestion. Notifying Google the change of domain in Google Webmaster Tool can help retraining your SEO as well. Regarding your question. I assume it should happen next time when Search Engine's bot crawling your pages? I could be wrong though. Maybe someone can give more insight on this.
I recently did the same thing to my site about a month ago (new domain name, 301 redirects, etc). All of my pages on the new domain were indexed by Google rather quickly, yet the old domain is still showing up there too.. I believe it said in the Google Webmaster Tools "change of address" page that it can take up to 180 days (6 months). Seems like an awfully long time.
It depends on several things... but primarily on how many inbound links you have from external sites and how often each of the URLs on those sites that link to you are crawled. You have to wait on them to recrawl each individual link, discover the 301 redirect for EACH link, and transfer credit for EACH link one-by-one. It should be noted that you will lose a little bit of PR or link juice due to the redirect because of the damping (decay) factor associated with PR calculations.
Thank you all for your replies. As I also asked, will there come a time when there would be no more SEO benefit to derive from the old site and one can then dump it or it is always advantageous to keep holding on to the old domain name and leave it permanently 301 redirected to the new site?