Ask a better question than how many years: which components are exposed, inspectable, maintainable and replaceable, and what written warranty applies to each part?
Durability starts at the base
Persistent moisture at lower timbers, poor drainage and splashback can shorten service life. Keep the base and surrounding ground in the inspection routine.
Follow the material instructions
Interior and exterior surfaces can require different care. Use only cleaning and treatment methods approved for the exact materials.
Keep a simple log
Record inspections, cleaning, treatments, leaks, door adjustment, heater service and replacement parts. Photographs make gradual changes easier to spot.
Frequently asked questions
What usually limits an outdoor sauna's life?
There is no single cause. Moisture management, exposure, construction details, installation quality, maintenance and replaceable components all influence service life.