Buy a guitar (probably used), tune it up....play it...love it!!!!!, buy it....take it home and still love it. Then the next day, week, month...whatever, you replace the strings.....and WOW!!! it sounds nothing like it did. The "mojo" done mojoed outa there. Then you call where you got it, trying to find what magical strings were on it....and really never quite do. I've had that happen several times, mostly pawnshop guitars. I think in looking back, it was the newness of the strings that changed the sound. It seemed as they were played more and strings got older the "sound" returned to some degree.

I find I can get a more "broken-in" sound out of a guitar if I use Ernie Ball Slinky's. They're really good strings, and great for that. Mostly I use Daddario's. But sometimes.......

-dave