Managing IP changes when using cloudflare

Hi. Cloudflare ( seems like a very useful service, and it appears to work well with Dreamhost, except that I have the following questions:

as I understand it, Dreamhost may (for management reasons) periodically change the IPs of our websites, and presumably it is then up to us to notify Cloudflare of the changed IPs;

so the questions are, (1) is that the case? and (2) if so, how often is it likely to happen? and (3) is there any notification to us from Dreamhost of when they do this?