The service schedule says 25k miles. I had mine done at service time recently with my car being at 57k.
Mine looked like they had never been touched before, which is usual as Honda service techs have habit of audibly checking at 25k and not even taking the cam cover off, yet still charging the customer.
My exhaust cam side were pretty close to being spot on, the intake side were well out, far too slack. If anything mine is a little noisier now, probably due to them being tightened up a bit.