Of course, every tank is different. Longevity depends on the quality of the initial build and materials.
My longest lasting plywood (900 gallons) tank went 17 years before I lost track of it. I'd moved it across country a couple of times when I transferred (Navy). It developed 2 leaks in that time that were easily fixed with silicone. I sold it to a petshop and lost track of it after the owner sold it on ebay.
like oddball said IF they are constructed properly
some dont even last their first filling
its hard to build one that looks good and will last for less than buying a glasstank unless you go big 240+
my 100gal plywood cost me $250 and lots of brain cells (epoxy fumes)
well im looking to build something huge hopefully 10-14' long by 36" who knows how deep.
this is going to be years in the planning and saving but the goal is to have a great clown knife and arowana tank that has plenty of room for them (especialy the knife) to swim a long distance without having to turn around.