This really depends on how well they are looked after, both when on display and when being stored. If treated properly they can last you many Christmas'.
Artificial greenery is not really made for the outdoors and the elements will affect it's longevity. For the best results we suggest using them indoors or under covered areas. We never advise using artificial wreaths or folliage outdoors if they have lights attached.
Traditionally wreaths are hung the front door of homes and office, but this is your chance to get creative. They look great hung in windows on on tables as centrepieces.