What all is in the tank? Test results?
The standard reply is that no, you can't do too many water changes. Most organisms do better with cleaner water. However--what size changes are you talking about? Several small changes are very different from several large water changes. In a FO tank, it's not as important, but in a reef, there's a balance. Many reef organisms are filter feeders--they require lots of little critters and particles to be floating around in the water. If you do lots of large water changes (40% or more), you're removing many of these organisms, and starving the filter feeders.
Of course, more frequent water changes means most trace elements will be constantly replenished, and that's a good thing. So, let's see what you have, and how many changes you're doing, and see if it's money in the bank, or just down the drain.