ITS recommends that all websites be behind U-M Cloudflare before they are migrated to Pantheon. If you integrate your website with Cloudflare, Cloudflare will handle a lot of the website's public visitor traffic without passing it on to Pantheon. This will result in Pantheon handling fewer visitors, in many cases reducing the size of the Pantheon rate plan you need and saving you money.
Because Pantheon will only let websites move to a smaller rate plan at the end of July every year, and only then if the website has been consistently below the traffic limits of the smaller plan, it may take up to a year of your website being behind Cloudflare before it can move to a less expensive rate plan. To avoid this possibility, ensure your website is behind Cloudflare before you move it to U-M Pantheon.