How often does Google change SSL certificates and how I would go about obtaining the new certificate?
You can anticipate that Google SSL certificates will be updated at a minimum of once per year, and it wouldn’t be completely out of the ordinary if they changed more often than that. There is already a facility for devices to follow the Google certificates as they change. See the section “SSL Security Hash” in Activating Devices: Instead of keeping certificates in the devices, the devices keep an SHA1 hash of the public portion of the certificate. That hash is compared against a hash received from google.com to validate the device is really talking to google.com. To allow for the transition to new hashes, there is an optional header that is passed to/from Google.
