Go by the look of the coral IMHO.
Most LPS don't "need" to be fed directally, but are allot happier when they are, not to mention grow faster. I have only seen a positve reaction from any LPS I have tried to feed, provided you give it the right thing (meety foods).
Because I have only seen an increase in growth, and a positive effect in how the corals look I do feed them, it makes them happy which makes me happy.
But, knowing they don't strictly need to be fed I don't stress over missing a feeding, or doing it too often.
On average I feed once a week or so.
One other little trinket,...
If you have a
LPS coral that is doing poorly, like bleached or receding, if it will take food feeding usually helps the coral turn the corner and start doing better. Of course if it's bleached putting it in the shade and feeding is the best course of action.
HTH,
Whiskey