Matching baud rate on serial monitor I am using different codes which set different values of baud rate through the Serial.begin() function. Do I need to change the baud rate of the serial monitor to match the initialized value on the code I am running every time, or can I just leave the serial monitor baud rate set at the highest frequency of all my sketches (115200)?
If your sketch has

  ...
void setup() {
  Serial.begin(115200);
  // ... other stuff here;
}
  ...


And you run the IDE serial monitor at 9600, you will get gibberish. The same happens the other way round. You need to match the monitor to the baud rate you've defined on the Serial.begin(); call.