Clearing sketch between projects?

If the arduino is set to run the program after receiving power then what happens when I move onto another project that doesn't use the same setup. In some cases this could potentially blow something. Should I hit reset on the board between each project? I don't see any mention of this in the book. I feel weird when I breadboard out the next project with the last project still loaded onto the chip. Should I disconnect everything from the breadboard and load the next sketch prior to building it on the breadboard? Really confused about what to do between projects. :(

If I hit reset on the board while Project 03: Love-O-Meter is running then it simply restarts the Project 03 sketch. It doesn't default back to the basic Blink sketch. How to ensure safety so that I don't accidentally blow up my Arduino between projects? Should I manually load in the Blink sketch between projects?

Just upload this sketch before you make changes to the hardware:

void setup() {/* Do nothing */}
void loop() {/* Do nothing */}

I've been loading the default Blink sketch in between projects. Seems to do basically the same thing you recommend except with the obvious blinking of Pin 13. Thank you.

DJDevon3: I've been loading the default Blink sketch in between projects. Seems to do basically the same thing you recommend except with the obvious blinking of Pin 13. Thank you.

If your new project has Pin 13 connected to +5, Gnd, or something that can't take 5V then the Blink sketch is not as safe a choice.

Woah. ok. Then I will be copying your code and saving that as my safe sketch. Thank you!