Even the most accomplished major-league hitter uses a conventional batting tee, often on a daily basis. Always revert to basics! The more advanced a batter becomes, the more important it is to anchor his style to a duplicable, definitive, consistent swing. Many times, a more advanced batter sees a successful hitter and, even on an unconscious level, begins to emulate the other swing and lose sight of his own. In addition, the success of a great hit (often, a home run or long fly ball) can influence a batter to make a subtle change in his swing in the attempt to duplicate his feat. Agan, a slight and imperceptible change in his swing causes ongoing problems.
The tee grounds the batter to his unique swing and reinforces his proper mechanics and timing. Using a tee is not a rote, mindless process. As much as possible, replicate game conditions: begin each at-bat looking toward an imaginary pitcher’s mound then adjust your sight to the ball on the tee. Move the tee to various locations, e.g. low and outside or high and inside or in front of the plate or toward the catcher. Simulate game situations, too, i.e. there’s a runner on third base and you lift a fly ball or there’s a runner on second and you must advance him.
The simplest things in baseball are often the best. Become the best hitter possible (measured against your potential) with a return to the beginning. Make it simple, make it basic, make it great!
From October 2010, http://raisingahitter.wordpress.com