If you want to ensure better degradation, you could upgrade your app to be more usable without the server. Drawing on your stamp example, you might add client-s

If you want to ensure better degradation, you could upgrade your app to be more usable without the server. Drawing on your stamp example, you might add client-side stamp storage and backup features. If the server goes offline, then you could even continue selling your app that way. I would not implement those features too early, though, since obviously you don't want to cannibalize the rest of your service.