That's how I used to do it until there was a 2 week wait on the part, more than once have I been surprised over the years and luck would have it my backup didn't break down too, but it could happen... Every once in a moon the part is discontinued and there's simply no more, too. But them's not the kind to have in the truck, spark plugs on the other hand, or a belt can ruin a day. Driving by the dealer, have to order the parts, whip out the credit card, pay... And go back home, three days later swing by the dealer again, get the part. Two stops, one part. Last but not least, ordering parts from aftermarket bulk is usually cheaper. Until we get the wrong part, anyway.