All outdoor furniture requires at least some maintenance, and that includes polyrattan. However, that’s largely limited to cleaning it of any dirt, debris or bird droppings that outdoor furniture inevitably accumulates.
The process for cleaning outdoor furniture made from polyrattan is very straightforward and you can typically use a hose to rinse it, or a special woven furniture cleaner that’s non-foaming. Do check manufacturer’s instructions, however, so you don’t void any warranty.
In the winter, check manufacturer’s advice on whether polyrattan outdoor furniture can remain outside; this really depends on the frame material as cheaper frames can rust. Covering the furniture with purpose-made covers in the colder months is a good idea if it does remain outside.