Warranties offered need to be negotiated on an order by order basis. Because this will vary from one factory to another.
Generally speaking factories offer a small percentage of spare parts – for free – to cover any breakages or faults.
Many manufactures will also offer a 6 month spare parts warranty. Here’s how it works. Once your order arrives, if you report any faults the factory will ship over the replacement parts or complete unit to compensate for this.
Why do factories offer these spare part warranties? Because in most cases, sending items back to China and then from China back to you (halfway round the world that is) is not a cost effective solution. And more over Exporting and re-importing is lot of paper work making is nearly worthless to sent the spares back.