When Georgios Maridakis' product breaks it's actually an intentional feature. His Clock Vase indicates time with a little hammer that knocks against the porcelain. And at the right stroke, it shatters.
There aren't any notes on how long it would take to wear out a vase on average, but the entire idea is to have different chime sounds due to switching the flower pots so it can't be too long. I just hope Georgios never decides to make an alarm clock like this, because just imagining the porcelain shards near a bed makes my feet hurt. [The Design Blog]