There's two ways you could look at this.
First....and there is some truth to this....you certainly don't want your tank looking BAD at any time of the month. If you wait to do your water changes when the corals look lousy, well, then, you've waited too long! It's a sad truth that problems develop quickly in this hobby, but take a lot longer to correct. So if you're changing water while the corals look "great," then you're doing a good job keeping the parameters on an even keel.
There's another way to look at this. Are you stuck on a rigid schedule for water changes? That's not entirely necessary. I would say that you should be aware of your tank's needs, and schedule water changes according to your (and I'm sorry to steal Mark Callahan's phrase) "tank personality." If your parameters are great, consider smaller water changes that are more in line with basic maintenance (siphoning detritus, etc) only.
Just don't be a moron like I was and forget to change your filter floss for 4+ weeks.
That'll screw you right up every time.