Of course, these oil changes & valve adjustments are relative to the life expectancy of the engine. I think (hope) Jims 600 hr est is conservative, my oil ch schedule exceeds OEM specs, I am ballparking the depreciation factor to 900 hrs @ 150 hrs per year = 6 years.
The 4th-century Tomb of the Lionesses consists of a small chamber with gabled roof. The painting depicts flying birds and dolphins and scenes from the life of the Etruscan aristocracy. The 6th-century Tomb of the Hunting Pavilion shows the view seen through the transparent fabric of the pavilion.
Etruscan architecture. A style which flourished in western central Italy until the Roman conquest; it is largely lost, except for underground tombs and city walls, but the characteristic true stone arch influenced later Roman construction methods.