Re: tennis newbie's questions
~ I generally agree with 1sun's opinion regarding Fed's racket (Wilson Ncode). It has a small head and thin frame. Not to mention that it is very light and that when you hit the ball,
~ While you're still beginning to play tennis, I recommend that you get a cheap/averge rcket. Unless you're rich, it would be quite a waste to buy an expensive racket when you start. Since you'd have to consider the size of the head, the weight, the length, the feel and the power it gives, your preferences would generally change as you get better. Like me, I started to play with a Prince longshot (large head and longer than average) but now I use a head intelligence racket which is shorter.
~ The Babolat racket (forgot the model name, the one roddick uses) I would have to say is one of the best choice.
~ You generally don't have to worry about your strings. But you must remember to regularly change your strings (which is also a good chance to experiment on tensions and string types). Hybrid strings are good (gut+synthetic) but they don't last as much as synthetic ones.
~ On coaches, unless you have money to spare, I generally discourage it. The ideal time to get one is when you're starting but that is only so that you can learn the basics with proper guidance. Once you know how to hold the racket, footwork, (etc.) then you could play without a coach. Since you could only get better with practice and regular play.
~ Invest on a good pair of shoes. This maybe one of the most important and practical equipment in tennis. Bad shoes provides poor support which could lead to injuries.
~ And since you're still starting you wouldn't notice much of a difference between balls that are slightly and heavily used. As long as they bounce normally, they are still good.