We only saw it used to check the most recent spell. We don’t know that it can’t go further back, and in fact in fanfics it often can go through the recent history of the wand.
The Priori Incantatem effect of the brother wands meeting certainly seems based on Priori Incantato (though why was never explained that I could recall) and that one certainly did go back further than just the last spell.
We only saw it used to check the most recent spell. We don’t know that it can’t go further back, and in fact in fanfics it often can go through the recent history of the wand.
But that’s not canon IIRC, which means that it should be assumed not to be the case unless EY says otherwise.
The Priori Incantatem effect of the brother wands meeting certainly seems based on Priori Incantato (though why was never explained that I could recall) and that one certainly did go back further than just the last spell.