[AHill]

It's not as simple as it seems. A store owner must consider extra investment in strings, time and labor to change them out, how many guitars need strings replacement, etc., then balance all that out with some wish that increased sales will happen. Another consideration is how does the owner determine which guitars need strings changed? Does he need to play every single guitar to figure that out? Does he mark each guitar with some tag that indicates the last time strings were changed? Does he remember the tone of each guitar? The $75 Fender that's brand new might sound like it needs a string change, but the $2800 Martin that needs a string change might still sound better. If I'm in a store and the guitar sounds like it needs a string change, I just ask and generally they'll do it for free. That seems like a better business model to me from an owner's perspective.