they can determine someone's appropriate level after watching a person hit for 5-10 minutes?!?! I see a lot of posts on here saying thing similiar to "after watching this person hit for a couple minutes he looked like he should be a 4.0." You may think that you have an idea of what the strokes and pace of a certain level look like, but what you can't tell after watching someone hit for a few minutes is what their mental make-up is. If you play tennis, you know that a lot of what happens during a match goes on upstairs - is a person a quitter?, do they cave in on pressure points?, do they dig in and get tough under pressure?, do they adapt to a new opponent's style quickly?, etc. I know a guy with solid and grooved strokes that refuses to play any type of match (even practice sets) because he can't handle the "stress" of live match conditions (what I find ironic is that he's a surgeon and works under stressful conditions all day in the OR). How many times have you found yourself thinking that you're in for an easy match during warm ups because your opponent(s) don't have the prettiest strokes only to find youself in a 3 set thriller because their mental game or on court thinking and problem solving skills are excellent? All I'm saying is there is a lot more to being a good tennis player than looking the part on a practice court.