I don't. Nor do I know if a band new one will fail. New does not always equal good.
I can also get a flat tire, have a fuel pump fail, have all the electronics fail, have the transmission die (again), have the starter fair, water pump leak, or a radiator hose break. Not to mention the timing chain can send valves through pistons or the oil pump can wipe out the engine. At 5 years and 119,000 miles, anything can happen. I've had brand new parts fail out of the box in the past so it is always a bit of a crap shoot.
Driving is scary stuff.
Aside from all of that, I just want to keep this thing going for a few more months. I don't want to buy until January, but GM seems determined to have me do otherwise.