The adjustments that matter
Only a handful of adjustments genuinely matter: seat height, seat depth, lumbar support, and tilt. Seat height should let your feet rest flat with your knees near a right angle. Seat depth should leave a small gap behind your knees when you sit back. Lumbar support should press gently into your lower back.
Everything beyond that — armrests, headrests, and recline angles — is personal preference. Do not pay a premium for adjustments you will never touch.
Materials: mesh vs. cushion
Mesh breathes, which keeps you cooler through long afternoons, but it feels firm. Cushioned chairs feel softer and warmer, which suits some people and bothers others. Neither is better for your back; comfort is what matters, because a chair you avoid sitting in helps no one.
If you run warm or your office lacks good airflow, mesh has a real advantage. If you prefer a softer seat, choose cushioning and accept the trade-off.
Match the chair to your body and desk
Chair fit is personal. Check the seat-height range against your desk height and your own measurements. A chair that cannot get low enough will leave your feet dangling; one that cannot get high enough will force you to hunch. Weight capacity and seat width matter too.
If you are unusually tall, short, or heavy, look specifically for chairs that publish their fit ranges rather than assuming one size fits all.
A chair is not a cure
An ergonomic chair supports good posture, but it cannot undo the effects of sitting still all day. The most effective upgrade is regular movement — standing, stretching, and walking every 30 to 45 minutes. Buy a good chair, then pair it with the habit of getting up.