Both times I've had mine replaced they put a temp charge on my credit card for "non-return".
With a DIY repair, they send new AirPods to you and expect the old ones sent back. Once they receive the old ones they drop the temp charge.
My first set of new ones it didn't go quite as smoothly as that. For some reason it was processed as a replacement not as a return/repair. So it took an actual call to straighten it out, but was resolved in 24 hours. The end result of that miscommunication was that they didn't expect the old ones to be sent back. So I ended up with 2 new ones and my old ones. I was having ANC issues with them which didn't really bother my daughter, so I bought a cheapo charging case from Amazon and gave them to her