I am looking for an idiom that satisfies the idea of giving away your second option instead of your first. For example you could have a really nice basketball and a not as nice basketball to play basketball outdoors with. Instead of choosing the really nice basketball (so as to not risk its quality) to play with you choose to play with the not so good one.
Basically you do not want to give away or risk your best "thing".
"Somewhat" along the idea of Mark Twain's “Don't use a five-dollar word when a fifty-cent word will do.”