I bought the used pair of K712 I'm using around three years ago, haven't looked back nor forward. The Moondrop B2 is about a year and a half old as well, no desire to change. I bought a pair of ADAM T8V last year and have been playing around with room acoustics for a while. I've always found the notion of spending thousands of dollars on headphones silly but even more now when I consider how great of a sound you can get with headphones with so little nowdays, even compared to powered monitors today.

I've also had the Topping E30 and L30 since 2021, absolutely no need to switch. Running the speakers from the MOTU M2, it started having audio dropouts a few months back after a windows update so that's slightly infuriating but in terms of audio performance I don't see myself changing anything in the signal chain.