I have a very accurate digital thermometer that is accurate to 0.1 deg C and it has been worth it. Can calibrate heater thermostats, and incubators and know the temperature is what I want. Haven't own a test kit for pH, or anything else for over 30 years but this has been worth it. Used one at work to test dishwashing machines, fridges and freezers and finally invested in one for myself. Best thing I ever did.