I had a rock crack my windshield about 3 months after getting my car.  Didn't replace it for almost 2 years even though it was in my line of sight.  Some insurances will cover cracked windshields - you'll still have to pay your premium.  Turned out that to replace my windshield, it was $520 (parts and labor), $20 more than my premium, so it wasn't worth getting insurance involved.  WELL WORTH it though.  Now, everytime I get in my car, I don't stare at the crack.
-Stink