Furnishing fifty workstations is a different job from buying one chair for yourself. When a chair has to survive eight hours a day, five days a week, across a workforce of mixed heights and body types, the questions shift from "is it comfortable in the showroom" to "will it still hold up in year four".

Start with the people, not the catalogue

Collect two numbers before you look at a single product: your team's height distribution and the ratio of sitting to standing hours. If your population spans more than 30 cm in height, a chair without an adjustable seat depth and a sliding lumbar pad will fit nobody properly. Flat-spec chairs are cheaper per unit and more expensive per year, because the people they fit badly stop using them correctly and the failure rate climbs.

What actually matters in the specification

• Seat height range. Aim for at least 400–520 mm. A narrower band forces shorter users onto footrests and taller users into a slouch.
• Seat depth. 380–430 mm of depth adjustment lets the front edge clear the back of the knee for users from about 155 cm to 195 cm.
• Lumbar support. Height-adjustable and ideally depth-adjustable. Fixed lumbar is a design decision made for the average user, who does not exist.
• Gas lift class. Class 3 as the floor, Class 4 for heavy-use or 24-hour environments. A Class 2 lift is a warranty claim waiting to happen.
• Armrests. Height and width adjustable, and able to drop low enough to sit under a 720 mm desk surface. Fixed armrests are the single most common reason a chair cannot be pulled close enough to the keyboard.
• Base and castors. Nylon base for general office use, aluminium where loads exceed 110 kg. Castors rated for the floor: hard castors on carpet, soft castors on hard flooring, braked castors for height-adjustable desks.

The standards worth checking

Two references do most of the work. BIFMA X5.1 (North America) and EN 1335 (Europe) both define dimensional types and durability tests — cyclic load on the seat, backrest fatigue, castor endurance, and impact resistance. Ask for the test report, not the certificate alone; a report tells you which tests were run and on which model. Also check the stated user weight rating: many chairs are tested to 110 kg but marketed without saying so.

Mesh, foam or upholstery

Mesh backs breathe well and hold their shape in warm rooms, but cheap mesh develops pressure points at the frame edge. Molded foam with a fabric cover feels better in cold climates and hides wear more gracefully. For shared or hot-desking environments, choose a cleanable, non-absorbent cover — fabric seats in a shared office become a hygiene issue within a year.

What to test before you commit

Order one sample per shortlisted model and run a two-week trial with five to ten people of different heights. Check three things: whether the lumbar pad stays where it is set, whether the castors still roll smoothly on your actual flooring, and whether the seat foam recovers after a full day. Foam that stays compressed at the end of day one will be flat by month six.

Budget guidance

Three tiers are worth distinguishing. Entry chairs (fixed armrests, Class 3 lift, limited adjustment) suit meeting rooms and short-sitting roles. Mid-tier chairs with full adjustment cover most office populations. Premium chairs justify their price only for people sitting six or more hours a day, or where the chair is a visible part of the workplace brand.

A useful rule: spend on adjustment range before you spend on materials. A well-adjusted mid-tier chair beats a poorly specced premium one for almost every user.