If you need them, you need them. If not, then don't. I've noticed that many people shoe their horses just for their own piece of mind, and in turn the horse suffers for it. Why do you feel that you need to make the decision? Something change about your horse? Lame? New discipline? These all play a factor. Personally, I believe the majority of horses can do their job better barefoot, but I do also see the need for shoes in certain circumstances.
We are not human beings having a spiritual experience. We are spiritual beings having a human experience. -Pierre Teilhard de Chardin