According to the Ford TSP (Technical Service Publication) for the 1996 Contour, the PCV valve should be replaced every 60,000 miles. Also:

Quote:
At 60,000 miles (96,000 km) your dealer will replace the PCV valve at not cost except on Canada and California vehicles.

1996 Contour SE Sedan 4D (Royal Blue)
Duratec V6 2.5L 24-valve DOHC
Automatic
75,000 miles
No Mods (unless you call the DMD a mod)
Replaced EGR valve (gunked up), EVR (EGR VR), PCV valve, and evaporative emissions hose (cracked).