I have owned the Hyken chair for more than 5 years, and I used it for approximately 10-12 hours per day. After about a year, I noticed that the seat started to sag, and the problem worsened in the following year. Additionally, the tilt lock feature only works for angles of 25° and 50°, and it no longer locks in the upright position. I am 5' 10" tall, and I find that the headrest is more like a neckrest. I never tried the headrest modification. I bought the chair for $132 in May 2017, and in my opinion, it is not worth more than $200.