If you decide you want to work with a coach, do your homework on the person. Ask to communicate with other runners she’s coached. Find out how long people are usually coached by him and why they no longer are. Most important, find out how individualized an approach she takes. Will the training you’re given be tailored to your running background, your goals, your rest-of-life situation? How often will you be allowed to call or write when you have questions or hit a rough few days?
If you get the sense that you’re being given the same program everyone receives, you could do just as well with a good running book or an online library of workouts.