RODI...changing the carbon, etc

[newreefer_59]

"If it ain't broke, don't fix it" I have always been taught.

I have had my Captive Puriity RODI running since March of 2009 - so like a year and a half.

Range it shows is still well within the green 'safe' range and is 0 TDS consistently (occasionally gives me a 1 or 2 ppm)

I was told to replace the sediment and Carbon abiut a year ago now, the DI should have been replaced by now. I know it is WAY overdue, but all the values tell me it is still working fine.

Should I replace these 3 elements NOW anyway, or wait until I start getting TDS?

Thanks.