I've never felt the need for idiot lights or gear indicators, except on the track. As Gerry said, when you're going for it, the last thing you want is to hook the wrong gear. I had a gear indicator fitted to my R1 when I was racing, purely so I didn't cock up in the first corner. The chaos of the first corner, plus loads of highly revving bikes around you, could easily make you forget where you were in the gearbox. Not a problem anywhere else. If it sounds right, you're in the right gear...