If you live in New York and have to deliver packages to both California and Texas, it makes sense to hit Texas first, while you're moving in that direction. Otherwise you're wasting gas in having to turn around and come back. That's the essence of Economy Picking.

http://en.wikipedia.org/wiki/Economy_picking

In all of your playing, the idea is to not waste gas. Unless you want to make it difficult just for show. Always ask yourself, "Once I get used to it, will it be easier this way?" Trial and error. Your technique will always be re-invented over time, so experiment with everything and find out why certain things don't work.

-Carl.