Test kits and frequency of tests that should be run?

[Trigger Man]

For me I keep testing each parameter till it is contantly the same, and then I may check the parameters again in a month or so to see if it is the same. If it is noticably off I try to figure out why and test till it is constant again. After it is constant I will check KH and Cal out every couple of months to make sure they are still constant and adjust as needed. I will also check certain parameters whenever I start dosing something new, or if I change salts.