Easy to use, you don't have to be a chemist to do the tests.  This kit tests for the most common and important pollutants and is cheap enough that you can monitor your well often.  It does not, however, test for everything.  If you live in an area that is industrialized or where pesticides or herbicides are heavily used, or where radon is common, you must have a certified lab do the testing as recommended by your local health department or EPA. This kit showed my water to pass all its tests but I still use a carbon filter like a Brita for my drinking and cooking water.