You got an OEM replacement? Must have cost you around $1000? I know aftermarket windshields are around $200 installed.
Windshield cracks are dependant upon where you live and how much you drive. They put gravel on the road here for snow, and there is a lot of construction going on, so I've already had a couple of good-sized chips on my windshield (which I got filled right away).
Just watch who you're following (Honda Civic, not as bad. A lifted truck with 33's and no flaps, bad.) Also, there are people that think the lane doesn't end on the white line, but on the edge of the shoulder, so they go driving right through all that gravel on the side of the road, flinging up all kinds of mess. I usually try to switch to the other lane to avoid paint/glass chips.