Valve lash is something that should be inspected about every 30k miles although I’m fully aware that many people do not do this either out of lack of knowledge of the subject or because it can be a heavy financial hit.
That recommendation you were told about only inspecting them when noisy is actually a ludicrous one.
Many car makers other than Honda state the same thing and many mechanics blindly follow this bogus advice.
What is not mentioned is that excessively loose valve lash can be determined audibly but what cannot be determined by the ears is whether or not a valve is tightening up or not. The quiet ones are the ones that can cause you the most grief because those are the ones that may burn a valve face and valve seat in the cylinder head. This is usually more applicable to exhaust valves due to valve stem stretch, etc.
The downside to loose valve lash is that cam lobes, valve adjusters, valve stems, etc take a beating and the engine loses a tiny bit of performance although you may not notice the latter.