Hello good people of Arduino Land. 
Further to my previous questions regarding the water drop controller build.
(Found here for those that may wish for some background):
https://forum.arduino.cc/index.php?topic=679995.msg4574730#msg4574730
https://forum.arduino.cc/index.php?topic=682458.msg4591064#msg4591064
https://forum.arduino.cc/index.php?topic=683588.msg4598692#msg4598692
I have decided to move away from potentiometers as a (timing) data input device - largely due to the 'mechanical memory' issue.
To wit, I have decided to learn about rotary encoders.
Aren't they wonderfully stressful devices?! 
Nevertheless, I have put together a very simple sketch which works well, and does not need interrupts - I will need six encoders, so working with a Nano will prevent the use of interrupts due to the interrupt pin limitations, and I'm certainly not clever enough to even begin to think about 'pin change interrupts' stuff.
I have placed some 0.1μF capacitors from the switches to GND as a crude debounce method, and as long as I don't rotate the encoder too fast, I'm getting nice clean counts on the serial monitor.
(I plan to use Schmitt triggers for all switches eventually)
I have used the encoder switch (shaft push switch) as a reset button - to reset the count to zero.
This is where my lack of understanding of the 'state change detection' is causing a minor issue.
I have read countless posts here regarding the debate as to whether a switch is pressed or a switch becomes pressed...I can only imagine the frustrations of those who respond to such posts with the same passage....over and over....you must have the patience of a saint....no names mentioned, but I bet you know who you are!!
Kudos to you all for your dedication and patience!!
So, please forgive me for adding to the ever growing list of those who have perhaps not grasped this concept!
When I press the 'reset' button on the encoder, despite me having written in the code for choosing a state change, I'm still seeing a stream of zeros while the switch is (albeit momentarily) pressed.
Here is the sketch:
#include <digitalIOPerformance.h> //Old library which speeds up response of digital pins - on 328 based Arduinos
#include <Wire.h>
const byte encoderPinA = 2; //DATA
const byte encoderPinB = 3; //CLOCK
const byte encoderSw = 4; //SWITCH
int encoderPos = 0;
bool encoderNowPinA = LOW;
bool encoderLastPinA = LOW;
bool swState = HIGH;
bool swStateLast = HIGH;
void setup() {
Serial.begin(9600);
pinMode(encoderPinA, INPUT_PULLUP);
pinMode(encoderPinB, INPUT_PULLUP);
pinMode(encoderSw, INPUT_PULLUP);
}
void loop() {
encoderNowPinA = digitalRead(encoderPinA);
swState = digitalRead(encoderSw);
if (swState != swStateLast) {
if (swState == LOW)
{
encoderPos = 0;
Serial.println(encoderPos);
delay(10);
}
swState = swStateLast;
}
if ((encoderLastPinA == LOW) && (encoderNowPinA == HIGH)) {
if (digitalRead(encoderPinB) == LOW) {
encoderPos--;
} else {
encoderPos++;
}
Serial.println(encoderPos);
delay(10);
encoderPos = min(98, max(0, encoderPos));
}
encoderLastPinA = encoderNowPinA;
}
....and here is a screenshot of the serial monitor and what happens when I press the button....
Ideally I would like to see only one zero.
In the grand scheme of things, I'm not sure yet whether this will make a huge difference in the final project, but I'm just curious if there is a way to do this simply.
I'm going to go out on a limb and guess that it involves millis().
Is there a neat trick to prevent those messy zeros from ruining my neat serial monitor?
Warmest regards and best wishes to you all out there!
Edit
I am using a Keyes KY-040 style encoder....I say style because I think it's a cheapo knock-off...but it looks identical...save for the 'Keyes' brand name....works well enough though.