I carry a loupe with me at all times but I must admit, since I had my latest cataract operation done, I have found it rather more difficult to use, especially without my glasses. My advice, for what its worth, is that inexpensive loupes can be perfectly OK but always stick with a lower magnification - ideally 10X. Once you go into the high magnification bracket, the area of undistorted lens available to use diminishes and the loupe becomes increasingly hard to use. Cheap loupes also tend to fall apart, when the screw holding the cover to the lens loosens and sometimes falls out. I think that I might invest in a quality loupe with a wider viewing area than the usual loupes now that my eyesight is not so good.