Starman and I were playing online last night and we found ourselves defending a game contract by the robots (3NT, I think). We were setting them, but there was a trick where Starman led a small diamond, declarer played the ♦10 and I covered with the jack. I then led the ♦9 back. Dummy had nothing interesting, but Starman was sitting on ♦Q7. He played the ♦Q. I pointed out to him after the hand was over that the ♦9 was equal to the ♦Q, so he could have played low, got declarer's ace out of the way (the ♦K had been played previously) and then the ♦Q takes another trick.
Starman thought about all this before saying, "I know I should be aware of honors down to the eight, but I'm no there yet." I see his point.
It's good to know your own limits.