I'd be interested to get a poll going on whether or not people like to sharpen their tungsten on both ends or just one. Opinions please!
One thing I'm wondering about is oxide migration in the tungsten electrode. The tungsten producers, for example diamond ground products, say that the oxides (e.g. lanthanum) make their way towards the tip of the electrode and are emitted during welding. Perhaps there's a benefit to using only one end of the tungsten and therefore keeping the oxide migration in the same direction, or perhaps there's a benefit to reversing this direction and distributing the oxides?
Also, I have to say that I am not a fan of cutting new tungsten electrodes in half, which loads of people recommend. Each piece of tungsten you use to completion, you end up with about an inch or more which you have to throw away because it's too short to hold in the collet with the right stickout. When you cut an electrode in half you create two of those inch long waste pieces. So you're just doubling the amount of tungsten which you paid for but can't use.