I've found that something called Fast Fret extends the life of guitar strings. It costs about the same as a set of strings and it is well worth the price. Besides, it's easier to use than to change strings.

Backwoodsman, here is a true story:
I was field picking at a bluegrass festival, playing my Taylor 810. A well known guitar collector came by and asked to try it. He picked it up, struck a few chords and said, "This is as loud as the Martin I just paid $10,000 for"! Someone else remarked, "And, it sounds just as good too".