The advice on how to protect wooden garden furniture can depend on if the furniture is new or old, untreated or pre-treated, and what type of wood it is made from.
Generally speaking, most wooden garden furniture is either tanalised or oiled. New and old softwood and hardwood garden furniture is usually maintained by periodically applying a garden furniture oil. If the furniture has not been treated for a number of years, has green or black staining, or has turned grey or silver, it will need several treatments to restore its appearance. See the question on 'how to clean garden furniture' for a step by step guide and the products we recommend.