Change Discolored RODI Filters Even if 0TDS?

[bzb]

I've gone through numerous threads of folks asking this same question, but my system is curious. I last changed these in 2021 so they're going on 3 years old. That was also the last time I really flushed the RO membrane.

I went ahead and pulled the trigger on a refresh kit from BRS since it's on sale, but here are the crazy stats after flushing the membrane this afternoon for 10 minutes.

Source water: 44 ppm
Post RO: 2 ppm (~95% rejection)
Rejection water: 58-64 ppm
Post carbon: 0 ppm
Post DI, which is reddish brown: 0 ppm

I have no major issues in my tank. Do I bother changing these filters as they visually look like they probably need it - not to mention that they're 3 years old - or save the $40 and wait until I start getting 1ppm in the output?

 

[Kershaw]

I don’t change DI resin until tds hits 1.
And sometimes a back flush will get it back to zero a little longer. Regardless of color. Mine changed color just filling my 145 gal tank. But still shows zero.