Exactly! ‘My headphones are so quiet now, could the speaker be dying?’ is something we got all the time. Most of the time when people clean their headphones, all the do is take a wipe or a brush (if you’re lucky alcohol) and clean the outside of the mesh. Half the time all they’re doing is pushing earwax through the mesh so you get a nice little wax puck when you open them up.
It’s gross, but it did feel good to be able to tell people they didn’t need new headphones, we just cleaned them for $15.
The Cheese Test (youtube link) is a great way to visualize this. If the food doesn’t rotate, you end up with hot and cold spots.
(This was just the first video I could find of someone performing the test for people who hadn’t heard of it, I didn’t listen to the video, only confirm that that’s what they’re doing)