If you change the tank water often enough, you don't need to test it. An aggressive water change routine will guarantee steady, safe water conditions for your fish. If you're hit and miss on your water changes, then you need to test frequently. API and Tetra both have reliable strips. You get the results in a minute or so. But, the strips I've used don't test for ammonia.
"Fear not, my young apprentice. Just change the tank water."