I look at plants as a redundancy mechanism and not substitute to already existing filtration and water changes. A sufficient plant mass will wipe out the water column from a vast array of organic build up, including nitrogen, and as such aiding at excellent water quality but plants can't do it all by themselves. Water changes are still essential to fill in the gaps plants can't.
The biggest benefit I see in plants is that they take up nitrogen at source, and partially and sometimes fully reduce heavy oxygen demanding processes such as nitrification...which as desired and essential it is, has its drawbacks. Nitrification is limited to the amount of oxygen in water and in the filter... That's why a fish tank with plants will always have better water quality than one without, and it is especially important to have plants if one's stock is on the high side....A heavily stocked tank is oxygen deprived by definition...
Yes, one can get away with a lot when keeping plants...
I've come to the same conclusion over the years, but I do use a TDS meter to give me an idea where I am at...I like keeping my tank TDS to bare minimum, i.e. my tap water measurement...It tells me if all is working as intended because it measures all dissolved ions in the water. I don't need to know what they are. I need to know if there is build up over time....
I am going to put a face on my nitrogen machines
And a couple of videos.
Underwater
And a most recent from today above water
Im not even old yet either!