I never used to get wrist injuries but I suppose that overuse and probably a change in technique to accomodate less mobility has shown me some new wrist weaknesses I never had before. I now have a ritual. I use kinesiology tape on my dominant wrist before I go to the courts. I also add a wrist wrap to lend support. This has almost completely eliminated injuries in this area and as an added bonus if I ever took to going with the wrist on any shot, it limits the range which is usually very good for a tennis player. Possibly the only place this could be a detriment is when serving.
I have tried the high end tapes and the low end athletic tape.
My new preference is 3BTAPE as found on Amazon.com
I also like the McDavid Wrist Wrap as an overwrap after taping. It looks like a wrist band so you don't have students or opponents thinking you have an injury to protect. It offers great support washes easily.