Made some changes to your site and now waiting for google to reflect those changes on google search and ranking ? Calm down abit, google takes some time to update the cache.
After how much time does google update the cache ? well this question don’t have any definitive answer.
Cache update time for google varies from website to website, depending upon the “importance” of the website.
Now this importance lies within google’s own algorhithm. Some sites might be new, low pr, but get quick cache update from google, because of many reasons including but not limited to, fresh content throughout the site, regular updating, not-blacklisted ip or url, etc.
So depending upon your sites importance, updating regularity, content quality and freshness, google might update the cache for your site in less than a minute, or maybe in weeks or months . . .
Although you can set the google crawl time for your site from google webmasters tools, but it’s not guranteed that it will affect the crawl time as per what you’re expecting.
So if you want to have your website or blog cache updated within no time, keep your site updated regularly, with fresh and original content ofcourse.