As a rule, use hinges roughly one third of the door or gate's width and add one hinge for every 750 mm of height. Standard interior doors take two or three 75-100 mm butt hinges, while tall or heavy gates need three larger strap or T hinges of 300-600 mm. Heavier leaves and ball-bearing hinges call for the larger sizes.

Galvanised hinges have a zinc coating that resists rust and suits outdoor gates, sheds and damp areas, while black hinges are usually japanned or powder-coated for a decorative look indoors or on feature gates. Hot-dip galvanised is the most durable outdoor finish. Choose stainless steel for coastal or highly exposed sites.

Fit a strap or T hinge by positioning the long leaf along the top and bottom rails of the gate and the short leaf or pintle on the post, keeping them level and square. Mark and drill pilot holes, then fix with coach screws or bolts through solid timber. Hang the gate with a small gap at the bottom so it swings freely.

Ball-bearing hinges last longer than plain butt hinges on heavy or frequently used doors because the bearings reduce friction and wear. They are recommended for fire doors, heavy solid-core doors and high-traffic entrances. Plain butt hinges are fine for light interior doors, while gates should use bolt-through strap or band hinges rated for the weight.