As for how often to test, in the beginning I found it more useful to test 1 - 2 times a week until I got a handle on things. Now, I only test 1 - 2 times a month to make sure my dosing schedule is still keeping parameters where I want them.
Dosing frequency is really as needed... It varies from tank to tank depending on what's being kept in it. I dose alkalinity buffer via our auto top-off, but manually add calcium 2 - 3 times a week.