there is never too loud for me,if at a certain volume an amp clips or a cone rattles,then back down the volume a notch and boom.not loud enough!
lot's of times,relaxing at home with a good cd i can find just right(slightly loud),but never too loud.

as a joke, i have 2 packs earplugs(from work),hanging outside the basement door as a warning.have a pack in my glovebox,also.