We've been burnt quite a few times with sudden IP changes these past few months from various hosts. Some providing not even 2 hours advanced notice.
I got announcement for an IP change today from Catalyst Host: "We have already assigned your new IP addresses to your VPS Account. We are giving everyone 2 Months to make this transition happen."
I wanted to give a big digital high-five to them for giving us plenty of time to deal with the change and put this out as the new 'standard' for IP address changes for providers in the future. I'm sure it cost them plenty to hang on to the old IPs for that long. Thanks for taking the high road, Catalyst.
The bar has been raised.