Car Fluids Spoil??

Yesterday I learned that motor oil goes bad if you don't use it after a certain point.  You know, maybe I should've known better, but I thought that motor oil, you know, never goes bad.

That may be why the big jug of oil Father used never seemed to work when I put it in my car.  The level on my dipstick never went up, and if I didn't put in more soon after I put in some, I felt enormous stress that I should.  It seems as though I never have an issue seeing the oil level in my engine go up after I use one of the newer quart bottles I have in the back of my car.

But I continue to look through the Internet for tips on using motor oil that's been lying around.  I've seen sites that say that you should dump motor oil if it's been open for year, others two years, still others five.  I was of the mind of giving the leftover oil in our garage to the county hazardous waste site, but some corners of the World Wide Web say I can still use it.  So, what's the correct answer?

And I did more research and discovered that the coolant I lug around in my car also expires.  Do I need to get rid of that, too??

Damn, this is getting confusing, and expensive.