You don’t need to buy a new television to go digital, but you may need some new equipment. Almost any television can go digital with a digital set-top box.
If you want to buy a new television, and you’re not passing your old set on to friends or family, it’s a good idea to dispose of your old television responsibly. The display device in old televisions, known as the cathode ray tube (CRT), contains hazardous substances such as lead, and older models may contain barium that can harm the environment.
The best way to minimise environmental harm from the disposal of old TVs is to take your equipment to a reputable, specialist e-waste recycler. The Ministry for the Environment's TV TakeBack Campaign has been created to boost TV recycling services in New Zealand.
You can find out more at http://www.tvtakeback.govt.nz/ 
alternatively contact your local Council or specialist e-waste recycler to find out what recycling services are available in your region.
RCN e-Cycle, Sims Recycling Solutions, TES-AMM,
RemarkIT are companies in New Zealand that accept old TV sets for recycling and they are the Government’s recycling partners for the TV TakeBack Programme.
No. Almost any television can be converted with a digital set-top box. If you are buying a new television, you can sell your old CRT television, give it away, or keep watching it by plugging in a set-top box.