Paid inclusion options tend to offer other perks as well, such as guaranteed revisits to update your listings (e.g., every 24 hours), guaranteed inclusion on any partners' Web sites, reporting to track your performance, and in some cases a review of your Web site to ensure its relevance. With paid inclusion you are guaranteed to be indexed by the search engine, up to the number of pages you have paid for, within a short, defined period.
Search engines do not like the automatic submissions, and by doing it by hand you know for fact that a submission has been completed. If you choose to use automated submission software, here are a couple of popular applications: Web Position Gold, Search Engine Commando, Agent Web Ranking. All of the submission suggestions assume you are interested in being indexed by the major U.S.-based search engines.
Check out the help files for each search engine for more information on how to verify that your URL is included in their index.
Only resubmit a Web page if a major change has taken place, where much of the content on the page has changed. If you were once listed, but have been dropped from the listings, wait a few days to see if your Web site is reindexed.