Over a year = no warranty.
Their response on my bearing replacement (bearings cost ~$6 for the PTap) - "We do a complete internals replacement, no way around it. We don't replace just bearings, ever."
I've read sites that have instructions on replacing the bearings, but didn't want to brick my Ptap. So, I paid the $300 begrudgingly. That puts you back into warranty on the hub. The reality is that if the test torque is outside acceptable range (~510ish), you can call them and have it serviced.
My recommendation would be to do that about every 11 months, since I've yet to have either of my powertaps stay at that range for longer than a month after getting them back from Saris. In fact, the one I JUST got back from Saris reads 529 right now. The other one is 564.
Saris was once covered with praise from consumers. I don't hear that nearly as much these days. Especially not from people that haven't bought the new wireless hubs (Which they said would cost me $1000 per wheel to "upgrade" to... *boggle* I can get new/built for that cost)
As soon as I work out the details, I'll probably make the switch to a crank based PM.