don't be penny wise and pound foolish
Definition from Wiktionary, the free dictionary
- Don't be careful when it comes to spending small amounts of money, but careless when spending much larger amounts.
- Don't focus on minutiae and lose sight of the big picture; don't obsess over tiny inconsequential efficiencies while glaring inefficiencies are going on elsewhere.
- Gregory Y. Titelman, Random House Dictionary of Popular Proverbs and Sayings, 1996, ISBN 0-679-44554-4, p. 59: "Don't be penny-wise and dollar-foolish"