Or when we are seeking answers to overly tough questions. Many times a spirit guide will assist you when you are experiencing trauma - be it physical or emotional. Other times you will notice subtle nudges, like a tap on the shoulder to alter your course. Some people need their assistance - at all times. Some people may never require spiritual assistance from a spiritual guide at all.
Some people can, and do, rely only on their higher self.
And the higher self is a spiritual guide. I've witnessed several apparitions in my day.