Checking scale accuracy
Here's a simple way to keep a check on your scale's accuracy, to make sure battery isn't running down or scale is malfunctioning. These are in grams, which I find is a more accurate way of weighing ingredients than ounces. Reach into your pocket and pull out some change.
One penny = 2.5 grams
One nickel = 5 grams
One quarter = 5.67 grams
Throw a few coins on the scale and check it. It may not be absolutely exact due to wear of the coins or the fact that these are not medically accurate scales but it will be far more than enough for baking purposes.