It is not just buying or making fancy furniture that finishes the job from your side. You also need to take good care of it, depending on its type. For example, concrete structures need regular check for cracks & leakages. Likewise, wicker chairs, too need their share of love and attention. A raw wicker chair is vulnerable to attack by moisture as well as heat. You can add different types of protective coatings so as to safeguard them and hence increase their life.
Opt for a good latex paint. Often, multiple coats will do the magic. Opt for a color which will match the theme of your room (or exterior). If you wish to preserve that natural texture, you can opt for a clear coating, or better, a wax coating. Also, make sure you do not expose your wicker chairs to direct heat (sunlight or fireplace), as it will dry up the moisture from the fibers.