Hmmmm....
Having owned a music shop until I retired in 2009 I must agree with Moosh &WayneP, if the stock is dusty, out of tune and neglected then you don't deserve to succeed imo.
I had a young lad come in just after school 3 times a week asnd he tuned every guitar, bass, mandolin etc' in the shop, I know how to look after people as I'm one of the old brigade (ask Kiogon, he knows about service too) The only problems having a shop are the people that come in to try a guitar or bass and then buy it online! When they get it and there's a fault they then bring it to me and ask me to fix it because 'you're the dealer for these'.
got very short shrift off me albeit very politely
What to stock? that was the hard part because if I had 6 strats and 3 tele's I would have the wrong colours It's one of the reasons I retired, the net killed it, you can't have it all ways can you? Net prices or a service? you choose.