Expressions (phrases, clauses, etc.), Ichidan verb
to be told or made to hear something so often that you (metaphorically) get calluses on your ears
Idiomatic expression
お祖母さんの昔話は耳にたこができるほど聞かされた。I've heard my grandma's stories so often that I'm heartily sick of them.
Also written 耳にたこができる【みみにたこができる】、耳に胼胝ができる【みみにたこができる】