Height judgement will depend on the picture the pilot flying is seeing, knowing where to look and what to look for is the secret.
When teaching the last stage of the approach and the flare and lastly the landing I explain to the student where they should look and why.
Then I fly the approach, flare and landing and count down the height above the runway starting at 100 feet.
The student observes and prints the call out height in the picture they are seeing, that really gives them a benchmark from which to get the picture.
There is a similarity between light aircraft and large jets......the jets call out the height above ground / runway in a voice prompt right down to touchdown......in fact the Airbus even tells you when to close the throttles... the retard call out..
I have been doing the height call out long before the big jets included height call out's as part of the approach and landing