Chain every 7000 km
Cassette every couple of years, or until shifting is rough
Tires 8000 km for road tires. 10000 for commuting tires
Brakes 3000 km for rim brakes
Wheels 20,000 for rim brakes

Obviously, commuting bikes that take on water, snow, ice, salt, sand, and general crappy riding conditions will wear out equipment much, much faster than the summer, dry bikes.