That's the school of thought I adhere to, too.
(LOL, think I got the 2's right. or rite. DANGIT!)
But with out a doubt murphy's law is in full affect (effect? I hate English) with our merry little band and crazy contraptions in that if you are 14 miles from home, you will need a #14 wrench. And of course, have every thing with you but.
Don't matter what tool or part. The one you don't have will be the one you need.