Whilst Hue's support pages don't mention this explicitly, it seems like you do not need to have the Hub Bridge connected to your home network all the time. This is because the Hub bulbs and Bridge run on Zigbee, which is a local radio-wave system. They don't work with WiFi. Having said that, if you remove your Bridge's internet access, you won't be able to control your lights when away from the home. But more than this, you also won't be able to go into the Hue app on your mobile phone and control the lights here. You can however use Hue switches and remotes (they have loads of accessories to buy) and these will control your lights just fine, since these devices also use Zigbee.