How often to replace golf clubs?

I am looking for specific answers like how often to replace the follow CATEGORIES: Driver/Woods, Irons, Wedges, and Putter. I am wondering because I have Cleveland CG2 irons that are a little worn down and I just bought a Taylormade Burner Superfast 2.0 and LOVE it. I am looking to buy new woods as well. Please help?