Originally Posted by lwto
YOu will find as I have about 90% of the general public will go on your recommendation.
I've had my own stringing business for 3+ years and this is exactly true. The vast majority of my customers ask me for my recommendations. You are the expert in their eyes. I ask them a series of questions about their style of play, level, what they want the ball to do (ie: more spin, power, etc) and make a recommendation. Even when they have been with me for awhile, they still ask me if they should switch or stay with the same string.
My advice, carry a few of each type of string but don't overdue it. Keep the strings diverse within each type. For example, carry smooth, textured and twisted poly strings.
Also, I keep no more than 2-3 sets of natural gut on hand to keep the overhead low but carry good quality. Don't skimp because you don't want to have to replace crappy natural gut when it breaks in a week. I carry Babolat only.