I should have clarified my statement. Obviously mechanical failures eventually end in uselessness. I have a 27y/o Silva Ranger model that will develop a minute bubble in cold or high altitude. it has always returned to normal with warming. It's accuracy is still excellent. Using a compass implies walking out is a better option than waiting for rescue. This may indeed be correct in some situations. I have concluded, for my own needs, to get the best compass'. I have my old ranger, a Silva matchcase combo and a Recta army unit. Im still looking for the smallest, liquid damped unit available for pocket kits.Compasses are like guns and knives: only accurate and sharp ones are interesting.