Despite my best efforts, in the past few years I have had no luck with desk chairs--each one I've had grows uncomfortable after 10-15 minutes of working. This discomfort manifests as sore legs, sore back, feeling too warm, poor seating posture, and similar inconveniences. I recognize the need to stand up and stretch periodically, but these uncomfy chairs make it really difficult to get into the zone.
Have you found a chair that makes you happy? Given the amount of time I must spend at a keyboard, I am willing to spend real money. For reference, I am a 40ish 5'10" male with an average build (pandemic deterioration notwithstanding).
I also have a treadmill desk, and it's great for humdrum work, but sometimes it is necessary to sit down and dig in when the task at hand is more challenging.
Due to lockdown restrictions I took a risk and ordered one without trying it first (knowing I had the return policy to fall back on).
I was immediately disappointed with the comfort when it first arrived, and almost sent it back. But I stuck with it for a few more days and found that once I'd adjusted to the chair, I now find it the most comfortable thing I've ever sat in. I've since read that it's quite common to take a few days to adjust to a chair like this, where the ergonomics are very different (better) than cheaper chairs.
I used to get various aches and pains after sitting in my cheap office chairs for a few hours (even with breaks in between), now I find that there is almost no upper limit for how long I can comfortably work in this chair.
So yes it's f*king expensive, but I do highly recommend it. A year on, I think it was a very good investment.
BTW I highly recommend the Atlas Headrest for the Aeron - it looks 100% like a genuine original part and it really makes a big different to comfort (in my opinion). The only downside is the headrest alone costs about the same as what I used to spend on "upper-range" office chairs from Staples.