when does a water change become irrelevant

[Magickiwi]

I monitor ORP because I run ozone and I do notice that after a water change my ORP reading hits the floor. I keep my tank around 325-350 between water changes but after a change it goes down into the 1xx range. It will take the better part of a week to get it back up. What does that mean in terms of the need or benefit of a WC? I dunno, but I'm not stopping my bi-weekly change to find out. I will let the braver people experiment with their tanks

Water clarity does seem better when my tank ORP is in the 350 range as does the vitality of the fish. Similarly my inverts etc. all seem to love the higher ORP readings.