When you use a wrench, your brain sees it as an extension of your hand and you can actually feel the bolt through the wrench instead of directly with your fingers. If not for this, your wrench would constantly slip off the bolt.
When you drive a car, the brake pedal is like that wrench. You can feel how much bite the brakes have, even though your only contact is through that pedal. You really don’t want to be "feeling" other cars on the road, which is why you look through your windows. As you do this, you constantly compare what you see with what you expect. If there’s a difference, you adjust speed or direction.
Using diagnostic tools is much like looking through your windows. Instead of reading road signs and traffic, you look at such things as voltages, waveforms, and temperature profiles. As with driving, you can’t usefully interpret what you see unless you know what to expect.
This is why you need to invest some time in learning the "road signs" and "traffic patterns" of any system on which you perform maintenance or repairs. As you figure out what you should be looking for, assess your diagnostic tools to determine if you have blind spots that a new tool would eliminate.
Yes, you should use your DMM to see if correct voltage appears on Contact 23B when Coil 5 drops out. But what should the waveform look like at the input to the forming press while the feeder is retracting? Can you see what you actually have?