and hold the Arduino in reset indefinitely. I find this to be 1000% useful.
Why would you need this?
Many sketches blink lights or ping piezos or cycle servos, and it's a PITN
to listen to all of that going on while you're editing the sketch. Holding
in reset is easier than pulling the power plug.
Also, I often use the Arduino board's USB port to connect to other boards,
especially ones with XBee, and if you hold the Arduino chip in reset, then
you can daisy chain the RX/TX pins. [my workbench usually has jumpers
going off in all directions].