You're asking a rather generalized question and also asking if it's "worth it".
Typically when this sort of question comes up, the counter-question to ask is... what are you doing (or at least trying to do) with your current gear that isn't work out as well you want?
Depending on the challenges you're having with current gear, the answer might be that you need to look at something else... perhaps a different lens, perhaps a flash, perhaps even a different technique. Sometimes it really is the camera body that's holding you back but we couldn't make that conclusion without some specific examples. And sometimes when the body is holding you back, the upgrade might not be just to get "next year's model" ... it might be to upgrade to a different class of camera entirely (e.g. 7D Mk II, for example... or a full-frame body as another example.)