There is no easy answer as all chassis materials have the potential to degrade. If your car is a keeper there is no substitute for regular inspections and attention. There are no magic life time protection systems. What TimH says re the lift makes so much sense and is the ultimate solution. If I didn’t have easy access to the underside a lift would be a high my priority list. I’m fortunate as I have a two storey garage so can easily roll back the floor and walk underneath the car. Not a week goes by without being under there for one reason or another. My chassis is easily inspected, wiped off with an old rag and a fresh coat of ACF50 applied when needed. That’s all I use and the chassis is as it left the factory.
