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.
Changing strings daily can get pricey and doesn't make good sense for most - but one thing that can be learned from daily string changes is how to quickly get a new set in tune - and to stay in tune.
Have you ever put on a fresh set of strings and meticulously tuned each string up to perfect 440, only to have the guitar sound all out of whack by the time you hit the first chord?
That's because new guitar strings will stretch for a while before "settling" in. It's the same problem for acoustic and electric guitars, and even worse for classical guitars with nylon strings.
A good way to address the issue is to help the string stretching process along by doing some "pre"-stretching.
This can be done once you have a fresh set on the guitar. Get all the new strings up to pitch with a tuner. Then, starting with the 1st string (E), gently pull on the string. While pulling, move the string from side to side.
Then play the string again and check it with the tuner. You will see that it has gone flat, maybe considerably so. Then repeat the process on the same string until the pre-stretching no longer causes the string to lose pitch.
Then "repeat and rinse" the process on the other strings.
All you are doing here is simply accelerating the stretching process that a new guitar string naturally experiences.
Caution - Notice in the above description the use of the word "gently"? You will need to "gently pull" on the string - not "yank" it! This can cause damage to the guitar nut if too much pressure is applied, so proceed with easy caution when pre-stretching strings.
Even with pre-stretching new guitar strings, there will typically be a little more stretch left in them when you get down to actually playing, and you will have to tweak your tuning for a while.
But you will find that you have speeded up the stretching process considerably by pre-stretching, and the strings will "seat" much more quickly so you can get back to the really important stuff...playing guitar!