It’s actually when I am am picking up and putting things away, not vacuuming. Stuff that requires attention, but not thought.
Anyway, one thing I’ve noticed is that I generally don’t much care for most pieces the first time I listen to them. I can appreciated bits to them, but the overall composition is largely lost on me. Subsequent listens, however, usually make a peice grow on me, as I pick out different parts and melodies that I missed the first time.
Pop music is usually good for at most 3 or so listens before I am thoroughly bored with it, but classical has enough complexity that I can listen to a piece multiple times (I’ve listened to rach 3 probably a couple hundred times (used to be my cleaning music)) and still notice something new that I hadn’t noticed before.
I think that is part of the reason people don’t get into classical as easily. It takes more effort for each individual piece to understand and appreciate, as opposed to a pop song that you can pretty much know how the whole thing will go after a few bars.