No publication is a staple of life. It's not bread and water. You have to make it noteworthy in people's minds and even in their hands as they're holding it.
The nature of the task needs to be renewed so people just don't feel that all the hard work is in the same groove all the time, under the same circumstances and in the same environment.
You need to have a redesign because familiarity breeds a kind of complacency.
I think in conventional magazine wisdom, you need to have a redesign every decade or so.
