Wednesday was the first "sub-70%" days since the 24th of August with 'weak faves'. I've learned to accept it since it happens about once a week, if not more.
The indicator to me is that if over two or three days horses are finishing within about 4 lengths over a mile, it means the reads are 'just successful'. This is represented on my data-base by yellow blocks and eventually these turn to a few 'oranges' when the horses beat my read (I stopped using 'red'. Psychologically hate seeing it on the screen).
And when I watch the races, I can usually tell about half way through the distance if the read has been successful. I tend to focus on the horse I am playing, back or lay, and watch its movements. I can tell when the jockey is comfortable or about to search for a way to get...