How often dose someone at your field loose a plane and can't fine it?

Get yourself a "Voltwatch" from Tower Hobbies for 10 bucks.
You can mount it behind a window, under a canopy, on or in the dash or anywhere you can think of and all it takes is a glance to check it out when you turn on your receiver.
One saved my 80" Mustang one day before the first flight, the battery had a bad cell but everything was working (for the moment) and when I flipped the switch I saw a red light flash out of the corner of my eye.