Know how much dishwasher detergent to use. Almost no one should be filling both cups - it can even ruin your dishes if you use too much. Check your local water hardness (water company website should have it) and use this guide: 0-3 “grains per gallon” hardness, 1 tablespoon; 4-6 gpg, 2 tblsp; 7-9 gpg, 3 tblsp and 10-12 gpg, 4 tblsp. I stole this tip from Mary Hunt.

[Kacie posted this tip to the Readers' Tips box. It originally appeared as a comment in The Complete Tightwad Gazette giveaway.]