I hate to say it a few years ago i threw out my test and just started to watch my fish. I do water changes when the water starts to look not so crisp or the fist start to act funny. all my fish get plenty to eat with a 1 or 2 day fast every 2 weeks. since i have switched to this feeding style all fish are growing seem happy and the water stays nicer longer. the one thing i have noticed is after i started to fast my fish like this even the less aggressive fish are more for the food i put in the tank at feeding time. which is good so that all fish are sure to get food.
I threw out my water test kits ( many people disagree with) because when i would test and something was off I would try to fix it an seemed to loose more fish. By watching my fish every day before i go to work and when i come home I can tell when something is up. water change and or filter cleans asap gets everything right and my fish are happy. I havnt lost a fresh water fish due to anything but natural causes in a while. there is the random fish sadly passes but the over all loss has greatly dropped. PH is the only test i would consider doing again but so far this is working well for me.