There's nothing like a fresh set of guitar strings to bring out the sound of the guitar. Extended bass tones, crisp highs, and a shimmering, "fresh out of the box" tone that makes you want to put on a new set every day!
When I was still a touring road musician I actually did change strings every day. I wanted a new set on for every show. There was some peace of mind in knowing that the tone of my guitar was going to be fresh, and the chances of breaking an older string in the middle of a set were greatly reduced.