It depends how popular your site is, how often Google's spiders typically come around, how deep in the site the changes have been made. Generally the period should be anywhere from 1 day to 6 weeks.

You should submit your site map once again and when ever you refresh your content your should ping search engine to re-index your website.

Better way to re-index your page is to get backlink from relevant, high authority and often crawled website. Sitemap too important for the same purpose.

You can set that from webmaster tool as well also majorly it depends how soon you update your content.

I believe that to get indexed faster is to go socialmarker.com and submit to it and it will be submitted to digg and all the others automatically, you will have to sign up for all the sites and then you will get submitted faste

Google take some time to index your site you just do on page work carefully like site map, quality content and a much more......

resubmit site map and should make quality back links on high authority websites but its not enough to index quickly and Google may take some time to re-index your site in SERP.

On an average weekly indexing can be considered but the it depends on the sites, some highly active forums are indexed in minutes as well.

It cant be said by any statement and it would not be good Google will re-index but it may take time you just can submit site through Google webmaster tools