If you do a search you will find the question on prop balancing in a number of threads, the question come up about every month. What you will find is some people like myself balance every prop they use and others never bother. Some only balance props after a certain size. I never bother to balance a spinner and others wouldn't dream of ever installing a spinner unless it is balanced. Spinners are in the center of mass and don't effect anything very much but the prop will. You will have to decide for yourself if it's worth the couple of minutes it takes to balance a prop. I don't smoke in my house but I do in my shop so when I have some new props I go out and have a smoke and balance them, maybe it's just something for me to do while I'm killing myself???