If you’re going to build earbuds that are symmetric, please be bothered enough to mark the right-side bud with red somewhere, or make them slightly asymmetric and put a little raised bump in the plastic so I can tell without even looking which side is which. Having to inspect the labels on the underside of the earbuds every time I want to put them in properly is just stupid and a bad user experience.
Update: Shoot, I checked the broken earbuds I just replaced. Indeed, there is a small plastic bump on the right-side earbud, so you could figure out which side was which in the dark. And those earbuds were even asymmetric, so the bump wasn’t strictly necessary.