
Cover it, or store it
A breathable cover in winter roughly doubles the life of a timber set. A sealed plastic sheet traps moisture and does the opposite.

Furniture that lasts is the greenest furniture there is. Everything else is detail.
The most sustainable garden set is the one you are still using in twelve years. A cheap set that warps, fades and goes to landfill after three summers has a worse footprint than a well-made one you keep - whatever it is made of.
So the questions worth asking are about durability and repairability first, and material second.

A breathable cover in winter roughly doubles the life of a timber set. A sealed plastic sheet traps moisture and does the opposite.

Hardwood does not need oiling to survive - it needs it to keep its colour. Left alone, teak and acacia silver naturally, which is a look, not a fault.

Feet or pads under legs stop timber wicking moisture out of wet paving, which is where rot starts on almost every set that fails.

A traditional bench set is about as repairable as garden furniture gets - every part is a plank, and every plank can be replaced. Look for FSC-certified stock and check the timber thickness rather than the overall dimensions.