Basically, I skip that service on my bikes. My faith and confidence in the service department is extremely low. People's experience is that few, if any, adjustments are actually done. So I take my chances with not taking it in for this service. I do all my routine maintenance, but valve adjustment is beyond my ability and desire.
I have an FJR with 30k miles, a ZX 14 with 18k miles, and my CBR has 5k miles. I had a VFR with 12k miles. None has had its valve clearance checked. I had a BMW with 24k miles a few years ago and I had it checked - they bent a valve and screwed it up. I learned my lesson.
One more thing, I buy my bikes new, I am the only one that rides them, and I don't do track days. All items in my favor.
'09 ZX 14