[Gareth]

No, it doesn't need to update anywhere near as often as your antivirus does. A firewall update is really just changes to the application itself, whereas the antivirus updates are the signature files that are used to identify a new virus. basically, every time a new virus is identified by the AV vendor, they need to issue a new signature file, so you will get many updates over a very short period of time (some companies collate the updates and release a daily signature, whereas others release them as soon as they're ready).