I am a reformed water change addict. At one point I was doing a 50% change twice a week (got free research grade ocean water).
I then went to 50% once a week.
Next was 50% every two weeks.
After I got the tanks balanced I never noticed a difference after cutting back the changes so I slowed. Then I learned of carbon dosing . . .
My planted tank had 3 water changes in 2 years, all of them were associated with flat worm dips.
Before I moved in April it had been 6 months for my 65g reef.
Now that I have a 125g reef plumbed into a 65g planted tank, I don't know if I will be doing water changes or not. So far so good, it's been about 6 weeks without any. My corals are doing better then ever, but the alage is not so good right now.
JME