Spirit Guides - Do They Exist?

What are spiritual guides? Who are they? Who has them? What are the advantages and disadvantages of having Spiritual Guides? How do we validate they are who they say they are and how accurate is the information they provide?

Are guides nothing more than astral predators who provide snippets of information for us to trust and become reliant on their connection to us? Since we are spirit ourselves why not rely on our own judgement and connections instead of giving our power away to an outside force. When spirit guides are seen. Could it not be a simple mind game technique by the entity to make themselves appear in a form acceptable to us???