A well-made commercial bouncy castle can provide several years of reliable service, but there is no fixed lifespan that applies to every inflatable.
Choose equipment built for repeated commercial use, inspect it regularly and keep accurate maintenance records. Most importantly, judge each inflatable by its present condition and safety rather than its age alone.
Good maintenance will not make a bouncy castle last forever, but it can reduce avoidable damage, improve reliability and help a UK hire business gain more value from every purchase.