So I've had my 24-70 lens for a few years now. And to be honest, I've never been blown away by it like I thought I would be. But I can't seen to be without it either. I don't have another walk around zoom to use while it's in the shop. I'm wondering if you all service your lenses regularly, or how I can tell if something is wrong with it, or if it's my lack of knowledge. If len's are can get out of wack over time.... Any thoughts?

