I was recently declarer in 7 spades. I had A 10 X X X of spades and dummy had K J X X X. We had all the outside stops and the only thing that could defeat the contract was a 3-0 trump break and a wrong guess. There were no clues as opponents didn't bid. I led a small trump from dummy to my Ace, and West discarded so East scored the Q. 1 down and a bottom as no-one else bid the Grand Slam.
My partner says that in a finesse postion he ALWAYS plays for the Queen to sit over the Jack in the absence of any clues from the bidding because it usually does but also because by always doing the same thing, you improve the odds in future hands. If instead you play randomly your chances of success are 50/50 but by always playing one way your chances improve. Is he right? I would have thought that it's a 50/50 chance however you play