I do think the age changes it. If it's an 18 year old guy asking about his girlfriend, I also would be like, "hey, that may be a bit much. Old ones are fine." cause they're young. The expectations are lower. If it's an adult woman asking this for her husband, I would say to not give it on their birthday. "Hey, here's my old pair. Happy birthday" may be a bit flippant, but saying, "Hey, I got a new pair, want my old one?" doesn't seem like a bad deal.
Also, we didn't see the post. Maybe the other gifts were also bad. Not saying that AITA isn't a dumpster fire. But he changed the factors and didn't give us all the information.
Edit: I just saw the post. He bought her airpods a few years ago and, with how he's talking, it sounds like he got his around the same time. His wife's are glitching and just generally failing, but his used ones are fine. He says she takes care of them as with the rest of her things. He has the option to get free, new pair. Yeah, that is kind of dickish. "Here's my old headphones that could very well be on their way out as well and have been worn for x years. Please enjoy while I get my brand new set that I've openly told you I don't need. Happy birthday."
If this wasn't her birthday, fine. But on the day? That kind of fucked imo
My mom is treating me to a train ride for my birthday. I'll get to ride through autumn foliage and enjoy tea and such. It lasts about 2 hours and I'm excited. π€