Patio furniture is exposed to all the different climate elements, from high heat, humidity, as well as rain and other moisture. You can make your furniture last longer if you clean the furniture from the various kinds of damage that occurs. If you have any type of wooden furniture, you can preserve the life of the furniture by treating and sealing the wooden aspects of the furniture with the appropriate products.
The basic premise of refurbishing your outdoor furniture is to clean it with a rag, perhaps sand it down with fine sand paper, and then use a clear coat wood sealant or varnish to put a nice protective layer on it.
You should check with your specific manufacturer, as there may be slightly different processes depending on the type of wood. Here is a good general video by Ron Hazelton.
Here is another video by How To Patio for teak furniture which is different depending on the look you want to maintain.