Over 19 years ago, my employer purchased an office chair for me to use. Being a man of above average size ("high and mighty" as the say in Great Britain) they thoughtfully procured an ergonomic BodyBilt S2504. (Now known as a J2504.)
Recently, the height adjustment of the chair failed (the gas cylinder) and I was afraid that this was the end of the ride, so to speak. But I contacted the company's warranty department for help. They responded quickly and helpfully. The chair is very much past its warranty period, so for $100 they sent me a replacement part and link to a YouTube video showing me how to install it. Fifteen minutes after opening the package, I was back in business.
It's remarkable to me that this chair has withstood almost 20 years of near-daily use. For fun, I conservatively calculated that I have spent at least 38,000 hours sitting in this chair. I'm thrilled to have it working again. This model currently sells for about $1,400 on Amazon with Prime delivery. Oh, and it's made in the USA. If you're looking for an office chair, for typical, large-sized, or differently-abled humans, I feel very confident in recommending their products. You might say that I have a lot "flight time," indeed.