Hello, I would like to share you one interesting issue that I'm facing with nowadays. Two of my client's website's title was changed a week ago and the title hasn't been changed on search results yet. This is weird because on previous changes we could see the change in one day. There is a weird delay here. What might be the reason for this delay?
You need to register the site in Google webmaster tools and you will see if there are crawling issues - and what generally the frequency(not the speed) of the crawl is. Frankly the site may never be crawled that frequently and it could just be coincidence that on previous occasions it was after you made changes.
Could be something as simple as you are looking at cached entries or the bots haven't visited those sites.
i agree with magda.you should sign up with webmaster tools to see if there are any issues that need fixing.It could definitely have been a coincidence in the previous instances
Try Updating the sitemap... and yes signup in G Webmaster Tools is absolutely necessary to find any errors.. And also try to bookmark the site using any social bookmarking sites to speed up the update ...
this isn't unusual, it just means google hasnt re-indexed those pages yet. i've waited a month before my page titles update!
IMO you need to get more links to your site, so you increase the chances of the bots visiting more often
Me to, if often takes a while. At least a week. In the future make sure your titles are the right length etc so that they look appealing in the SERPS results.