You can also do the engine off range check by programming the elevators full up, rudder full left or right, and ailerons full left or right. If the model is big enough, you can usually see the elevator and rudder deflect when you hit the end of your range. If the model is smaller, have a person watch for full up elevator and give you a signal.

Don't forget to reset your failsafe before flying.

The person that says its pointless to range check with failsafe on probably assumes its hold mode and not failsafe. Even if failsafe is programed to hold mode, you can still range check it.

Walk away while constantly wiggling the sticks to full extremes. When the surfaces stop wiggling, you are at the end of the range. Again, you might need to another person to watch for the servos starting to act sluggish and then stop.