Indefinitely. Products fabricated from similar materials have been used in gardens for a long time without significant weathering. Each plaque is made from the highest quality materials, and professionally engraved with a personalised message and style. The engraved letters are coloured in black for presentation purposes and although the black colour fades with outdoor use, the engraving becomes more prominent as the plaque gets dirty over the years. You can buy a plaque with confidence that it will still look good in years to come.

*The chemistry of aluminium alloys is interesting. Given that it's a reactive metal (more so than iron) one would expect it to naturally corrode more rapidly than it actually does. The reason it doesn't is that the initial formation of an oxide layer on the surface protects the base metal underneath. Anodising is a process which forms a particularly structured and dense oxide layer which protects the underlying metal giving a long lasting weatherproof material ideal for outdoor use.

Due to the tree plaques being laser cut from sheet metal, there can be some very faint surface scratches. However they are unlikely to be noticeable and reflect the expectations of an outdoor product.