Cushions and comfort
The cheapest upgrade that changes the most.
Most people spend two thousand on a chair and sit on the foam pad it came with. The cushion is what decides whether an hour in the chair is comfortable.

If someone is in a chair for more than an hour at a time, the cushion matters more than almost any other component, and it is the one people skip. Pressure, posture and temperature are all cushion problems. This is also the one category where we will tell you to talk to a clinician: if there is any history of pressure injury, cushion selection is a medical decision and not a shopping one.
What we are reviewing
In review
3 more we are working through.
These are real needs we intend to cover. We have not put a name against them yet because we have not finished checking, and a recommendation we have not verified is worth nothing to you.
How to choose
The three things that decide it.
Match the cushion to the seat, not to the person's weight
A cushion wider than the chair sits in a dish and stops working. Measure the seat frame.
Air, gel, foam or hybrid
Foam is cheapest and compresses over months. Gel spreads pressure and adds weight. Air redistributes best and needs checking. Hybrids are the usual right answer for everyday use.
Any history of pressure sores changes the rules
Stop reading retail advice, including ours, and get an assessment. This is the one thing on this site we will not advise on.