After the 48-hour period has expired which is the timing that CL considers appropriate to avoid scam, you are free to renew your posting. For free ads, log into your Craigslist account and click the “Repost” link on the home page. From there you will be able to browse a list of all of your listings active, deleted, and non active. Click the “Renew” button to move your post back to the top of the listings in that category and will have your ad on the top, unless your competitors post more ads than you ad will o down. You are free to do this every 48 hours, but renewing does not extend the lifespan of a post beyond the normal 30 days, Renewing or Reposting the ad in case it got deleted , ghosted or flagged by your competitors or CL itself.