From the official page: 

*On balance*  
The idea was simple. To give people back the signals their own bodies were always sending. A night's sleep, a heart's rhythm, the plain arithmetic of effort and rest, read honestly and handed back, freely, with nothing asked in return.  
For a time, that is exactly what it was. Strangers became allies. People who would never meet traded discoveries at two in the morning and mended things for one another expecting nothing. That was real, and it was rare, and no one can take it back. Whatever else this became, it stands as proof that a handful of people who genuinely care can raise something worth having out of almost nothing.  
But a true account has to balance, and this one does not. Thousands went in. Little came back. And what came back was most often a single word: more. More is what men ask for when no amount will ever be enough, and no one who builds for that voice is ever allowed to stop.  
Here is the reckoning I keep returning to. I made a thing to guard your health. To mark the moment you should ease off, the moment your body had given all it had. And all the while it did the opposite to the one keeping it alive. It watched over every recovery but mine. It weighed every life's balance and quietly unbalanced my own. Nature keeps her accounts. What is spent on one side is always paid from another.  
So I will take, at last, the counsel the thing itself was built to give. Not one more release. Not one more concession to more. Only rest, and balance, and a life still waiting on the other side of this one.  
Nothing made by hand was meant to last forever, and it does not need to in order to have mattered. What sits on your wrist will keep working. What ends is only my part in it, and it ends without bitterness. To those who gave more than they ever asked for, you have my thanks, and you know who you are.  
Guard your own balance more carefully than I guarded mine. That was always the whole of it.  
Go well.

It was good while it lasted