who told you that?!? by regular water changes, we mean replace between 10~30 % of the tank water once a week.
if you're having wate quality issues, the easiest way to resolve them is 10% water changes at a rapid interval. lots of small water changes are better than a few big ones for helping fish through a crisis period.
--EDIT--
What/how many fish do you have, what size tank, and what exactly are the conditions you're concerned about?