Wood Quality
Is it solid teak (versus teak veneer or mixed woods)? Solid teak is more durable, resists moisture, etc.
Origin (e.g. Burmese teak) often adds value.
Finish & Joinery
Joint type (dovetail, mortise & tenon, etc.) makes a big difference in how long it lasts.
Finish (varnish / matte / polish) should match indoor use, avoid toxic finishes if children / pets.
Comfort
Cushioning / upholstery: foam quality, fabric durability.
Seat height & depth: should suit your height, usage (relaxing, reading, etc.).
Design Style
Carved vs plain; traditional motifs vs minimalist.
Armrests or none; backrest height.