I've probably had my GHD for about 6/7 years now and it's still in fantastic condition. Granted, I only use it about twice a month because I prefer to leave my hair natural, it's been with me on weekends away and trips overseas. I love that when I do use my GHD, a few swipes and less than 2 minutes later my hair is sleek and shiny and I am ready to head out.
I don't enjoy curling my hair with the GHD though, I find that it's more time consuming than using a traditional tong. I suppose it's also because my hair is very long so it's not as practical to curl with.
Every girl needs to have a GHD in their life.