I just checked my sitemaps web crawl stats for my areyourated.com and it displayed that the googlebot tried crawling a page from my website but it had a 404 error so I must have missed a chance for being indexed into Google. Is there a time limit or approximated time frame for the next crawl?
A 404 will cause the spider to come back, if it finds your site it will index it, otherwise if it keeps getting 404 errors it will remove you if all pages are 404. How often it will come back is not known unless your site has an update history where spiders will frequent it for fresh content.