First of all a little info - I have three Wordpress sites on a Cpanel/VPS - one a clients and 2 my own. I have had the client site (site A) a year and the other two (site B) 8 months and (site C) 6 months. Site A was a rebuild for a long standing domain so it has been steady traffic from gitgo. The last two are new IP's that have been growing traffic, but really just came out of the sandbox and got indexed. I do foresee having to upgrade my VPS as sites B and C grow, but the traffic and hits don't seem to add up. I have minimal Wordpress plugins on each site, all of them very popular (all-in-one -seo, better WP security, Google XML sitemaps and Timely all-in-one calendar on site C). Limit Logins and Secure Wordpress instead of better WP security on A and B. My CPanel/VPS security is still out-of-the-box. I have the same theme on site A and B, diff on C. So it does not seem to be a theme issue. I have W3 Total Cache (W3TC) on A, but not B and C. I have the Timely calendar on B and C, but not A. I have disabled the calendar to see if that affects the traffic over next day or so. It has had issues , but not traffic related as far as I know. Could W3TC make that much of a difference in bandwidth usage? I joined each of them to Google Analytics on Feb 24th. But while traffic has grown on C, site B has seen traffic shrink and only had 1 hit on March 7th, when the bandwidth usage was a massive 280. Is this just a natural outgrowth of my growing traffic and hackers probing a new site for vulnerabilities? Would a firewall help in this matter? I'm just a bit in the dark here.