I’ve had these for a while now and broke them an a few months back, but continued using them taped together. I decided to replace the tape and superglue the broken part, then I sanded down the glue until it was flush, then I added a vinyl skin to cover up the glue. I also changed out the old battery with a cheap higher capacity battery I found online, and I swapped out the ear muffs with better ones I found online. I did have to spend a little bit on this stuff to fix them up, but still a fraction of the cost of getting even a refurb pair. I think they turned out pretty well.
I have the WF-1000XM4's and they're alright. Annoying to fit in my ears but it's usable. But then my battery suddenly died within minutes of using one day. I thought I was crazy because I bought them used but practically unused and used them for about 2 years without any problem, then all of a sudden it basically dies. But then it turns out I'm not crazy because loads of people are having the same issue. The speculation is that Sony's firmware update shorted the battery, possibly due to new batches using different batteries, but their code to "optimize" said different batteries basically destroyed everyone's shit.
I'm trying to get the bastards to replace my shit even though I bought it used with no warranty. I've already bought batteries to replace, but I'll probably just return an empty box to these bums and keep the new buds, problem is they no longer sell them new on Amazon.