[morsch]

Regular school buses appear to be in service around ten to fifteen years.

https://www.quora.com/What-is-the-average-life-span-of-a-sch...

https://www.quora.com/What-is-the-average-life-span-of-a-sch...

[SkyPuncher]

I suspect it varies wildly on region. Rust is the biggest enemy in places that get snow.

From that, I suspect seats get beat up.