Look
Iron balusters are slim and give a more open, modern, or classic wrought look. Wood balusters feel warmer and suit traditional or farmhouse homes.
Durability
Iron is strong and resists dents and kicks. Painted wood can chip and may loosen over time, though quality installation helps a lot.
Maintenance
Iron needs only occasional dusting. Painted wood may need touch-ups, especially in homes with kids and pets.
Cost
Simple square wood balusters are often the most affordable. Iron costs a bit more per piece but frequently delivers the bigger visual change.
Check compatibility with the retained handrail
Balusters need to fit the rail and walking surfaces as part of a complete guard. A slim iron profile and a turned wood spindle may use different mounting details, even when the overall length appears similar. Ask how the old parts will be removed and whether their holes can be reused suitably or require repair. Retaining a handrail is a design choice that also needs a connection assessment.
Wood profiles can have shoulders that must align with the rail slope, while iron systems may use shoes or other fittings at their bases. Compare these details on a sloped section and a level landing. A product sample is useful for judging proportion and finish, but it should not replace measuring the actual stair and reviewing appropriate guard spacing.
Plan patterns and finish work together
Iron twists and baskets can create a decorative sequence, but the repeat must work on shorter sections and landings. Sketch the arrangement before ordering rather than assuming a pattern from one photograph will fit every run. Wood offers square and turned choices with different visual weight. Review either material beside the newels so the assembly looks balanced.
Painted wood and stained wood have different preparation needs. Iron coating names may also differ between suppliers, so compare physical samples where possible. If the retained rail is being refinished, coordinate that preparation with removal of the old balusters. Clarify which touch-ups are included on treads and post bases, because a material change can expose marks beyond the infill itself.
Compare the installed scope, not one component
Count stair and landing balusters separately, and ask whether fittings, removal, repairs, and finishing are included. Material price alone does not describe a usable installed guard. Secure attachments remain essential with either wood or iron, and an unstable existing edge should be protected while the replacement is incomplete. Choose the style only after those installation requirements are understood. Note whether newel positions stay fixed and whether the retained rail needs refinishing. Those choices can affect the number of fittings and the surrounding repairs even when the replacement baluster quantity appears unchanged.