How to decrement a variable in every line of a loop..?

Projects Programming
34

Those lines are full of patterns.

You should look into arrays and structures, the magic combination of arrays of struct, and the https://docs.arduino.cc/learn/built-in-libraries/eeprom/ EEPROM.put() and EEPROM.get() commands that can read/write (and update) a whole table worth of information in one line like these:

EEPROM.get(333,dayDates);
dayDates[7].date = 22; 
EEPROM.put(333,dayDates); 

EEPROM.get(93,onOffSchedule);
onOffSchedule[7][1] = 6;
EEPROM.put(93,onOffSchedule);

EEPROM.get(33,activeBits)
Serial.print(activeBits[7][4];

EEPROM.get(1,regularSchedule);
Serial.print(regularSchedule[0].morning_hour_off);
...

As for arrays of structs, the Flashing multiple LEDs at the same time tutorial has several examples of using arrays of structs to extend the BlinkWithoutDelay example to multiple blinking LEDs.

I'm sad that https://docs.arduino.cc/programming/ doesn't mention 'struct', and array - Arduino Reference doesn't even hint at, and almost discourages arrays of structs.